This document outlines the agenda and methodology for a research project on self-reinforced fibre polymer composites, with an emphasis on the fibre/matrix interface. The research will involve theoretical and experimental investigations of the interfacial properties, quasi-static properties, and low velocity impact properties of four types of self-reinforced polymer composites. Fractography and correlation studies will also be conducted. The goal is to better understand the relationship between interfacial properties, mechanical properties, and impact behavior, while addressing gaps in current literature regarding these composites. Thermal analysis, laminate preparation, mechanical testing, and microscopy techniques will be employed in the study.

1. Preparation And Characterization Of Self
Reinforced Fibre Polymer Composites With
Emphasis On The Fibre/Matrix Interface
By
Sharan Chandran M
Reg No: 13PHD0122
Under the Guidance of
Dr. K. Padmanabhan
1

2. Agenda
1. Introduction
2. Literature review
3. Gap in the literature
4. Aim, Scope & Objectives
5. Methodology (Theoretical & Experimental)
6. Interfacial Characterization
7. Quasi-static Characterization
8. Drop weight Impact and Damage Characterization.
9. Correlation studies in mechanics and mechanisms
10. Conclusions
11. Acknowledgements & References
2

3. Introduction
 Improved energy efficiency and reduced fuel consumption have
become increasingly important in order to stay competitive in the
transport industry.
 Aerospace, marine and cargo industries see constant pressure to
reduce fuel consumption through light weighting.
 The use of light weight polymer composites have helped in this
regards.
 Self Reinforced Polymer Composites (SRPC) provide most of the
solutions.
 A light polymer matrix is reinforced with it‟s own family of materials
as reinforcement(s).
 Varieties of Pseudo-Self Reinforced Composites (SRCs) within a
class of materials are also possible. Some of the SRCs like that of
Polyethylene (PE) and Polypropylene (PP) are lighter than water.
 Interface stronger as there is molecular entanglements and even H-
bonds rather than a weak van der waal‟s forces.
3

4. Classification
4
Self-Reinforced Composites
Polymeric Non-polymeric
Polyolefin(PE,PP), PA, PET,
PMMA, elastomers, polyurethane
and natural polymers (protein
based, cellulose based etc.) based
fibre reinforced laminates,
Honeycomb, foam
Carbon/Carbon
Metal/metal
Ceramic/ceramic

5. Applications
 Air, sea and road cargo containers
 Biomaterials
 Personal baggage and luggage
 Electronic packaging
 Marine industries
 Consumer products
 Automobile interiors
 Aircraft interiors
 Some of the polymeric SRCs float on water despite
their shape like PE, PP and their foams.
 Armors and ballistic
applications
5

6. Capiati and
Porter
(1975)
J. Mater Sci
FIRST SRC - HDPE SRC-Excellent Interface strength analysed due to (a) Trans-
crystalline regions were grown, (b) partial melting of fibre and matrix due to close
melting point (c) epitaxial bonding.
Research to develop an alternative for the anti-ballistic market resulted in the development of Self-reinforced
HDPE composites (KAYPLA™) which were also used in panels for caravans and vans.
Marais and
Feillard,
(1992)
Compos sci
technology
(HDPE SRC) filament winding for prepreg then prepregs moulded @ 10 MPa and 132
⁰C
(a) Chemical compatibility and processing temperature are the key factors.
(a) Specific mechanical properties were found promising in the fibre direction at
various temperatures.
(c) Found development of trans-crystalline region.
Hine et al
(1993)
Compos sci
technology
(HDPE SRC)
Hot compaction and film stacking. Exploiting the difference in melting temperature of
outside sheath and inner core.
Guan et al.,
(1995 and 1997)
J Appl Poly Sci
(HDPE SRC)
prepared by injection molding under low pressure. Effect of mold temperature studied.
Highly improved tensile strength ( 23 to 87 MPa) and modulus of (1 to 3.5 GPa) due to
(a) shish-kebab crystalline structure
(b) orientation of molecular chains along the flow direction
6
Literature Review- Earliest Contributions

7. Authors Literature Review- Important Milestones
Deng and Shalaby,
(1997)
Biomaterials
First UHMPE/UHMWPE SRC- tensile strength; tensile modulus and creep
resistance were significantly improved-Proposed for biomedical applications.
Lacroix, Werwer and
Schulte, (1998)
Composites Part A
UHMWPE/LDPE composite was first manufactured by solution impregnation
method followed by preparation of prepregs and hot compaction. Tensile
properties were improved, compressive strength was very low. High toughness
and biocompatibility-suitable for applications in ballistic and artificial
implants.
Barkoula et al
(2005)
Poly Compos
„overheating‟ in the production of SRCs in different systems of PP, UHMWPE,
PET and PA
Hine, Olley and
Ward, (2003)
polymer
PP SRC- „first Overheating‟ method. fibre surface also melts along with the
matrix was also studied. It was observed that this causes better wetting
compared to the traditional method.
Alcock and Pejis
(2004)
Composites Part A
Developed commercial PP SRCs. Got patent for PP SRCs
7

8. Author Some of the latest developments
Duhovic (2009)
Macromol mater eng
PA 66 SRC was first developed. Good interface obtained by pre-melting.
PA6 SRC was first developed. Tensile modulus 200 % improved, ultimate
strength improved by 300-400%.
(Huang et al., 2014)
J Appl polym sci
Presented an approach to simultaneously improve the mechanical
properties, fatigue and wear resistance of radiation cross-linked UHMWPE
based SRC.
Interface
Mooney Mcgarry (1965) Reinforced plastic comp Single fibre compression test
Kelly and Tyson (1965) J Mech. Phys. solids Fibre fragmentation test
Miller,Gaur et al. (1987) Compos. Sci. technol Microbond test
Griffin et al. (1988) Ceram. Eng. Sci. proc. Fibre pull-out test
C.Y. Yue and K Padmanabhan (1999)
(Composites : Part B)
Multiple fibre pull-out test
8

9. Authors Impact analysis - Literature Review
Alcock et al. (2004)
Compos Part A
Influence of processing parameters on PPSRCs made with tapes. Decrease in
penetration impact resistance of PPSRC with increase in compaction
temperature.
Established Delamination, tape fracture and tape debonding as the main energy
releasing mechanisms.
Barany et al
(2009)
Poly Test
Decrease in penetration impact resistance of PPSRC with increase in compaction
temperature confirmed again.
Y swolfs et al. (2014)
Composites Part A
PPSRC-influence of compaction temperature, dwell time and the application of
interleaved films on the tensile and LVI properties analysed.
9
Authors Other Important Quasi-static analyses
Barany et al.
(2009) Poly test
PPSRC-Film stacking followed by hot compaction, tensile characteristics went
through a maximum as a function of comp. temperature.
Ajji et al.(1992)
V Stern T et al. (1996)
Von et al (1998)
LDPE/UHMWPESRC (chopped fibre)-modulus and UTS increased with fibre
content modulus increased with T, same effect with increase in fibre length UTS
less dependant on T.
Bhattacharya
(2009) Exp poly letters
PA6/PA6-Excellent mechanical properties reported, Effect of polymorphism
suggested.

10. 10
Composite
Average Maximum
Load (kN)
Average Maximum
energy absorbed (J) Reference (year)
Self reinforced PP tape
(mass = 67.3 kg)
at an impact energy of 342 J)
>20 296.9 3 (2017)
E glass (unidirectional)/polyester resin (at an
impact energy of 80 J)
>5 38 6 (2012)
E glass (plain weave)/polyester resin
(at an impact energy of 80 J)
7.9 50 8 (2012)
Plain weave aramid/phenolic resin
(at an impact energy of 80 J)
8 >120 10 (2012)
E-Glass/Polypropylene
(Impact energy of 105 J)
>8 >40 7 (2014)

11. E glass/ (Cray Valley)polyester
(at an impact energy of 227 J)
12 >140 4 (2003)
E Glass /epoxy ; Cycom X-823 RTM
(at an impact energy of 227 J)
>10 >140 12 (2003)
Glass-polyamide/polyester hybrid
(at an impact energy of 227 J)
14 160 14 (2003)
Glass-polyethylene terephthalate
(PET)/polyester hybrid
14 140 5(2003)
Woven S2 Glass / toughened
epoxy (at impact energy of 122 J)
>18 90 9 (2009)
IM7 (GP 6000)Graphite/ toughened
epoxy (at impact energy of 122 J)
>10 120 15 (2009)
Hybrid Woven S2 Glass-IM7 graphite (GP
6000)fibre/toughened
Epoxy (at impact energy of 122 J)
>14 95 11 (2009)
11

12. It is evident from the literature that though some key research has been undertaken on SRCs in
general and SRPCs in particular, the following knowledge gaps can be identified in the
following domains.
 Interfacial properties are important parameters in the overall performance, efficiency and
reliability of composite materials in general. But, comprehensive studies conducted on the
nature of interfaces of polymer SRCs are virtually absent in published literature.
 Microbond Single fibre pull-out test is the most common test adopted for evaluating the
interfacial properties of composites. Microbond multiple-fibre pull-out test is not widely
explored in many of the systems though this recent method is a statistically averaged and
reliable method of evaluating interfacial properties of fibre polymer composites. This is also
the only method that addresses the issue of volume fraction of fibres.
 Not much attention has been paid to quasi-static properties of SRPCs, like the in-plane shear
strength.
 Not much emphasis is given to dynamic property analyses of polymer SRCs from an
interface property perspective.
 It is essential to get a relationship between size, time and scale effects on various materials
in order to get a proper understanding of the influence of these factors on different materials.
Such a correlative study of interfacial properties, quasi-static properties and low velocity
impact properties of SRPCs are absent in published literature.
 Fractographic characterization and it‟s correlation to interfacial, quasi static and low
velocity impact analyses are observed to be gaps in the literature.
12
Research Gaps

13. Present Investigation Leading to the
Doctoral Dissertation
13

14. Objectives of the Present Research
 To conduct theoretical investigations and experimental methods of interfacial
analyses on four systems of SRPCs (PE-PET/HDPE, UHMWPE/LDPE,
PP/PP, PA66/PA6) by using meso-mechanical multiple fibre pullout tests and
to compare the results with micromechanical formulations by Chamis and
Rosen. This study also correlates the FTIR and fractographic studies with the
observed test data.
 To study quasi-static and low velocity impact behaviour of all the four
systems.
 To conduct a comparative study of the interfacial properties, quasi-static and
low velocity impact properties of all the four types of SRPCs and their
damage characteristics with respect to an evolutionary coefficient defined by
us.
 To conduct fractographic studies on the pull-out, quasi-static and dynamic
post failure samples and to investigate the cause and nature of fracture and
failures and their implications with respect to the fibre/matrix interface.
14

15. Methodology
15
Literature review,
Problem definition
Material selection
(PE-PET/HDPE, UHMWPE/LDPE, PP/PP, PA66/PA6)
Thermal Characterization to determine processing window
(DSC and TGA)
Laminate PreparationPull-out sample preparation
Optical microscopy to evaluate blob
parameters
Quasi-static tests (Tension,
Flexural and in-plane shear)
Low velocity impact
test
FT-IR
Fractography (Optical
inspection, C-scan, SEM)
Correlation with evolutionary
coefficient
Micromechanical
comparison
ConclusionConclusion
Evaluation of interfacial parameters

16. Materials used in the Research
16
HDPE
(Matrix)
PE-PET
copolyme
r fabric
Density –
0.93-0.97
g/cc
Density
0.95 g/cc
Melting
temperatur
e 125⁰C
Melting
point >
250⁰C
Atactic
PP
(matrix)
Isotactic
PP
0.92 g/cc 0.9 g/cc
171 ⁰C 279 ⁰C
Nylon 6
(matrix)
Nylon
6,6
1.084
g/cc
1.14
g/cc
220 °C 264 °C
LDPE
(matrix)
UHMWPE
0.910–
0.940 g/c
m3
0.930–
0.935 g/cm3
120 ⁰C 130 ⁰C
(1) (2) (3) (4)

17. Thermal Characterization
 In order to determine the melting temperature of
each components, to find what type of tacticity
and conclude on the cohesion between the
different layers for a given temperature, thermal
analysis is conducted. There are also four major
thermal events that can be observed in polymers:
weight loss, glass transition, crystallization and
melting.
 DSC (Differential Scanning Calorimetry) is a
method for determining the thermal
characteristics of the materials. The principle of
its operation is to measure the variation in the
difference of temperature Δt between polymer
sample and reference when temperature of the
oven varies. This heat flow is directly
proportional to the heat capacity of the material at
a given temperature.
 TGA (Thermo gravimetric analysis) is a thermal
analysis which consists in the measurement of the
mass variation of a sample depending on time, for
a temperature or a given temperature profile.
 Melting points should also be close as much as
possible, because higher the MP of matrix, the
better will be the thermal stability of the
composite. 17

18. DSC of PE SheetDSC of PE Fibre
18
TGA of PE sheetTGA of PE Fibre

19. Processing of SRPC Laminates through hot compaction
 The fabrication of the
polypropylene self reinforced
composites sheets (400 x 400 mm)
are done by using hot compaction
method.
 Two sheets of PE constitute the
external sides of the composite
whereas a central PE sheet
separate three layers of woven PE.
 The assembly is introduced in an
oven at the ambient temperature,
and then heated to processing
temperature during a period of 1
hour, after this time the oven is
switched off and the composite
cooled slowly inside the oven until
the inside temperature reaches the
ambient temperature.
 Vf (fibre volume fraction)= 0.75
19

20. Theoretical and Experimental
Investigations
20

21. Micromechanical Formulations
 Inplane shear strength in MPa can be calculated by using
Chami’s prediction as
𝐹 = 𝜏 𝑚𝑢 𝐶𝑣[1+ (Vf-√Vf)(1- (Gm ⁄Gf)]
τmu is the matrix shear strength in MPa, Vf , is the fibre volume
fraction, and Gm and Gf are the matrix and fibre shear modulus in
GPa respectively. Cv is a factor representing the voids in the
system.
 According to Rosen’s prediction, shear strength is modified by
introducing composite shear modulus and the shear strain and
the formulation is
τcomp = F tanh(γG12/F);
G12 is the composite shear modulus in GPa, γ, is the shear strain at
failure. (E J barbero;Design with Composite Materials;CRC Press) 21

22. Multiple Fibre Pull-out Test Formulations
22
 Interfacial intrinsic bond
strength (τ)
 Peak pull-out force (F)
 Interfacial shear stress
(τf)
 Interfacial Frictional
stress at peak load (Ff)
 Static Coefficient of
friction (μ)

23. Multiple Fibre Pullout Test in Restrained Top Loading Condition
 In order to determine the shear strength of the interface between a fibre and an encapsulating resin, it
is necessary to exert a controlled shearing force to displace one phase relative to the other.
 The most common means of doing this is to hold the resin and place the fibre in tension (a pull-out
test).
 When the fibre is of small diameter , it is likely to have a low breaking strength and, if the force
required to shear the interfacial bond greater than that which the fibre can sustain in tension, the
fibre will rupture first and abort the bond strength measurement
 The interfacial contact area is kept at a small value, there is a high probability that debonding will
occur before fibre rupture (and before matrix deformation).
 The setup consists of a Microvise made of aluminium with brass plate to hold the fibre bundles at
one end which were inserted through the plate on the Microvise later on tightening it with screws
where the other end was glued with cardboard sheets and gripped to the UTM.
23

24. 24
θ
Optical
microsco
py of fibre
to
measure
fibre
diameter
Contact angle
measurement
Testing

25.  The load causes the shearing of the drop through the fibre thus giving the
maximum load encountered by it. Once the maximum load condition is reached,
the sample fails and the load starts decreasing. Further the matrix starts sliding
along the fibre bundle.
25
PP
Maximum Load

26. 26
Fibre surface characteristics of all the four systems (A qualitative comparison)

27. 27
IFSS Vs blob length plots
PP SRC

28. 28
IFSS Vs contact angle plots

29. IFSS of different systems subjected to pullout test
System
Number of fibre
bundles
Minimum
(MPa)
Mean(MPa)
Maximum
(MPa)
SD
PE-
PET/HDPE
Triple 4.8 5 5.3 0.205
UHMWPE/
LDPE
Single 4.6 5.1 5.4 0.330
double 4.3 5 5.3 0.419
triple 4.2 4.9 5.4 0.492
PP Four 35.1 41.58 43.8 3.691
Eight 10.5 15.32 18.3 3.214
PA Single 5.1 5.3 5.8 0.294
Triple 4.7 5.1 5.4 0.287 29

30. Types of interfaces & characterization techniques
a. Molecular entanglement
b. Electrostatic attraction
c. Interdiffusion
d. Chemical reaction of different groups
e. Chemical Reaction by forming of a
new compound
f. Mechanical interlocking
30
 Scanning electron Microscopy
 Transmission electron microscopy
 Scanning tunnelling microscopy
 Atomic force microscopy
And Various spectroscopic studies like
 Fourier transform Infrared Spectroscopy
 Auger electron spectroscopy
 Raman spectroscopy etc.

31. Fourier Transform Infrared Spectroscopy
31

32. Fractrography (PP)
32
Friction ridges on fibre surface
matrix
Longitudinal crack
propagation
Amorphous
rough matrix
Interface
failure
Microvice
contact
failure on
blob

33. Summary of interface analysis
1. Multiple fibre bundle pullout technique is a reliable alternative choice over the conventional
single fibre pullout tests in many aspects as it is a statistically averaged test method,
addresses volume fraction and reduces the chances of fibre breakage and least dependent on
blob length.
2. Viscosity of PE is less compared to PP and PA. This causes difficulties in fabrication of
pullout fibre samples. But helps in better diffusion into the fabric. Still, PE fibre surface is
self lubricating and results in getting lower IFSS.
3. Single fibre pullout test fails in many cases when the fibre load under tensile loading
condition is lower than the load taken by the fibre- interface. Thus by multiple fibre pullout
technique, it was found that the interfacial shear strength of the self reinforced polymer
composites are comparable to conventional fibre reinforced polymer composites, though on
the lesser side.
4. Polypropylene (PP) based self-reinforced composites (SRC) showed better interfacial
strength (around 41 MPa) compared to other self reinforced composites due to strong
wettability aroused from chemical compatibility and molecular entanglement. PP matrix
possess an optimum viscosity infuses into the gaps of the individual fibres and results in a
strong interface which was not observed in PASRCs in microscopic examinations indicating
the reason for weak interface.
5. UHMWPE/LDPE SRCs showed interfacial strength of IFSS of around 5 MPa.
6. Micrographs show that PP is more infused into the fibre bundle and fractographic studies
substantiated the objective of this analysis.
7. Weakest interface among all SRCs was that of PA SRCs which reflected in reduction in it‟s
overall mechanical properties too.
8. It can also be concluded that the selection of the method of interface analysis is also
depending upon the nature of the fibre and matrix materials emphasizing a need to develop a
proper guideline in selection of the test method.

34. Quasi Static Tests
Tensile Tests were conducted with standard
specimens. It was necessary to follow the procedure
set out in the standard D 3039 / D 3039 M – 95 A
proposed by ASTM.[30]
Flexural Test with ASTM D 790 M was followed
for three point bending test [31].
In-plane shear Test determines the adhesion
between the fibre and the matrix. Two notches are
made in each sample at 12.5 mm from the half-
length on either side .
34

35. 35
Flexure
In-plane shear
PE SRC
Tension
Load Vs extension plots from quasi-static tests

36. Quasi-static SRC properties of PESRC
PE SRC (Tension)
Maximum
Load (N)
Ultimate
Tensile stress
(MPa)
Strain at
Maximum Load
(%)
Young’s Modulus (MPa)
Maximum 1505 20.043 2.822 2976.42
Average 1376.4 32.02 1.607 2764.99
Minimum 1260.6 17.564 0.975 2429.24
Standard
deviation
122.73 1.543 1.05 294.01
PE SRC (In-Plane
Shear)
Maximum
Load (N)
Ultimate Shear
stress (MPa)
Shear Strain at
Maximum Load
(%)
Shear Modulus (MPa)
Maximum 1248.276 2.00 1.201 2731.38
Average 841.145 1.35 0.988 2479.486
Minimum 534.94 0.86 0.669 2191.238
Standard
deviation
367.222 0.59 0.281 271.9
PE SRC (Flexural)
Maximum
Load (N)
Ultimate flexural
stress (MPa)
Flexural Strain at
Maximum Load
(%)
Flexural Modulus (MPa)
Maximum 147.58 51.93 5.1 6582.563
Average 140.05 41.5 5 5952.267
Minimum 130.58 37.2 4.9 5617.555
Standard
deviation
6.57 6.13 0.07 431.274
36

37. Quasi-static properties comparison (% Change from
pure matrix)
37
0
252.7
0.769
-42.85
100.362
68
38.000
-68.7
376.18
69.6
-37.550
-89.2
89.33
73.16
90.438
51.56
PESRC UHMSRC PPSRC PASRC
Tensile strength Young's modulus Flexural modulus % strain at yiled

38. 38
Tension Fibre failure under Tension
Flexure ridges (compression side)
Flexure
PP SRC
Crack initiation
Interface
lamellae

39. 39
PP SRC subjected to In-plane shear loading
Fibre
subjected
to shear
failure
Above
notch
below
notch
Below
notch
Above
notch
Shear flow of matrix
Transcrystalline
layers

40. 1. PPSRC is more brittle among all SRCs and micrography revealed features of such
fracture in all the tests.
2. PPSRCs are exhibiting excellent interfacial strength compared to PESRC because of
higher intrinsic bond strength of PPSRC compared to PESRC and PPSRC exhibited
brooming type of phenomena under in-plane shear failure.
3. Shear flow patterns were indications of the nature of fracture in matrix.
4. Matrix cracking, interfacial debonding, fibre pullout are the major cause of failure in
PE and PP while delamination was the main cause of failure in PASRC due to weak
interface.
5. UHMWPE SRC exhibited high IPSS (287 MPa) than all the other systems due to
less notch sensitivity compared to PP SRCs and excessive crack tip plasticity.
6. PASRC was able to support much higher loads and more flexible compared to PE
and PP SRCs. Still all the laminate properties seem to be reduced compared to pure
PA 6 due to weak interface.
Summary Quasi-static tests

41. Low Velocity Impact Test
41
Parameters for drop mass
impact test by using Instron
CEAST 9340 by ASTM
D7136/D7136M-05
standard
value
Length (mm) 150
Width (mm) 100
Thickness (mm) 3±0.5
Drop heights (mm) 600,900,1200
Impact energy levels (J)&
velocity (m/s)
32(3.42),48(4.18),58(4.6)
Effective drop mass (kg) 5.5

42. Force-Time Characteristics of drop mass impact test
42
PE

43. Force-Displacement Characteristics of drop mass impact
test
43
PE

44. 44
PESRC UHM/LDPE SRC PPSRC PASRC
2254.35
2431.47
840.28 1192.89
2402.07
3328.75
886.45
1240.4
2561.50
4141.58
869.66 1247.620
Average Maximum Load (N)
32J 48J 58J
PESRC UHM/LDPE SRC PPSRC PASRC
30.7
18
15.06
26.42
42.6
27
15.04
38.25
44.3
36
13.06
41.352
Average Energy absorbed (J)
32J 48J 58J

45. Energy profile diagram
45
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
0 10 20 30 40 50 60 70
Absorbedenergy(J)
Impact energy (J)
Nylon
UHMWPE/LDPE
PE
PP
900 mm
height
1200 mm
height
600 mm
height

46. 46

47. 47Scan axis
IndexAxisImpact area
mapped
Through transmission C-scan

48. 48
48
Sample
32 J 48 J 58 JPESRC

49. 49
4949
Sample
32 J 48 J 58 JPPSRC

50. 50
PESRC UHM/LDPE SRC PPSRC PASRC
984.71
292.35
3350
26.42
939.01
518.15
2921
38.25
735.14
862.90
2589
41.32
Surface damage by optical method (mm^2)
32J 48J 58J

51. 51
Cross section through the eye of impact of PESRC and
PPSRC which suffered penetration

52. Impact Fractography
52
PE SRC

53. Summary of Impact analysis
1. Under low velocity dynamic load conditions, load carrying capacity is drastically increased
due to strain rate sensitivity. For PP SRCs the strength increases by five times and for PE
SRCs, by 15 times from their quasi-static values. PE SRCs have higher ultimate load under
dynamic loading compared to PP SRCs. PE SRC had the superior impact property among
all.
2. Perforation energy threshold limit is also found to be higher for PE SRC all other SRCs.
3. Damage is more localized in PE SRCs compared to PP SRCs. UHMWPE SRC and PA
SRC were not subjected to any perforation. When the impact energy increases growth of
damage area is at a more rate for PP SRCs compared to PE SRCs. Damage growth is
restricted in PESRCs within a small area even under higher energy levels by utilizing the
energy for fiber fracture, bridging , fibrillation and matrix cracks. It was noticed that at the
higher impact energy levels, surface damage on PESRC is seen and most of the energy is
spent in perforation reducing the impact on the surface. This also indicates that a weak
nature of interface assists in a localized perforation. It can be concluded that PE SRCs are a
better choice for dynamic loading conditions.
4. Energy profile diagram and damaged area analysis are very useful in predicting the
behavior of the elastic-plastic SRC materials subjected to dynamic loading.
5. Fractography is thus able to corroborate the observed test data with the observe fracture
features as PE SRCs are more elastic –plastic than the PP SRCs are seen through the load
time and load displacement plots, that indicate the superiority of PESRCs over that of the
PPSRCs under drop weight loading. 53

54. Correlation (PE)
Test
Method
t/A
ratio
(s/mm2)
Force evolution
coefficient
𝐹/(
𝑡
𝐴
) (Nmm2/sec)
Energy evolution
coefficient
𝐸/(
𝑡
𝐴
)(Nmm3/sec)
pullout test 0.32 43.75 0.625
Tension 0.373 7,075.446 4,178.571
in-plane shear 0.0288 71,468.75 26,041.67
Quasi- static
flexural 0.45 311.2222 1,088.889
PE 600 0.00033 6,763,061 92,109,000
PE 900 0.00031 7,861,345 139,418,200
PE 1200
0.00026
3 9,706,751 167,868,600
54

55. Test
Method
Stress evolution
coefficient
(Stress/t/a)
(N/s)
Strain evolution
coefficient
(Strain/t/a)
(m2/s)
Pullout 31.25 3.125
Tension 49.017 0.0267
Inplane 46.875 0.3125
Flex 92.22 0.1111
55
Correlation….

56. 1. A complete overview about self reinforced Self reinforced composite materials was obtained when
we analyzed these materials based on their chemical structure, design parameters, operating
parameters, phenomenological concerns, and interfacial properties rather than analyzing these
materials just based on the mechanical properties alone.
2. Even if three systems of these materials belong to the polyolefin class of materials, an additional
CH3 bond on polypropylene chain causes weak packing in the crystal structure of PP compared to
a more closely packed orthorhombic PE chains. This could be one reason for weaker strength of
PP SRCs under dynamic loading.
3. Thermal processing reduces the thermal stability of PP SRCs more compared to PE SRCs which
can be observed from the comparison of their TGA data. PP SRCs form better interface with their
own matrices compared to PE SRCs due to a lubricant nature of PE SRCs. Still, that could not help
in its overall dynamic loading performance of these composites.
4. PESRC was the superior in overall mechanical properties (flexural modulus improved by 376%
young‟s modulus by 100%, % strain 90%).
5. Though PASRCs have weak interface impact strength was commendable. Impact strength is
mostly depending upon the fibre strength and interface properties have least influence on low
velocity impact strength as the load is applied in a very short interval and in transverse direction.
6. UHMWPE/LDPE composites are suitable for ballistic applications as it has very high impact
strength and constrained damage area.
7. An evolution coefficient between load, energy, size and scale and time parameters was formulated
which was found to be useful in analyzing the evolution of performance of various materials
under pull out, quasi-static and drop weight impact. It can be used as a quantitative tool to
correlate the quasi-static properties with those of the dynamic ones.
8. A high specific absorption value in low velocity impact tests of PE and PPSRCs render them
useful in cargo and luggage applications in the marine and aerospace domains at affordable costs.
Conclusion

57. 1. Studies can be conducted on self reinforced,
foam and sandwiched composites which will
offer ultralight applications.
2. Fibre surfaces can be modified by chemical
treatments to improve the adhesion.
3. Numerical analysis can be performed for
multiple fibre pullout and impact tests.
4. Multiple fibre pullout tests can be improved to
reduce scattering.
5. Guidelines and standards can be prepared for
interface analysis.
Future scope

58. Publications
1. M. Sharan Chandran and K. Padmanabhan (2019), “Microbond fibre bundle pullout technique
to evaluate the interfacial adhesion of polyethylene and polypropylene self reinforced
composites,” Appl. Adhes. Sci., (Springer), 7(1), pp. 5.
https://link.springer.com/article/10.1186/s40563-019-0121-z
2. M. S. Chandran, K. Padmanabhan, D. K. Dipin Raj, and Y. Chebiyyam, (2019), “A comparative
investigation of interfacial adhesion behaviour of polyamide based self-reinforced polymer
composites by single fibre and multiple fibre pull-out tests,” J. Adhes. Sci. Technol., (Taylor &
Francis), 34(5),pp.511-530.
https://www.tandfonline.com/doi/abs/10.1080/01694243.2019.1672467.
3. Chandran, S. M , Padmanabhan, K; Maxime Zilliox , Constanstin K Tefouet (2014), Processing
and Mechanical Characterization of Self Reinforced Polymer Composite Systems , International
Journal of ChemTech Research, 6, 3310-3313.
http://sphinxsai.com/2014/vol6_6_ICMCT/3/(33103313)ICMCT14.pdf
4. Sharan Chandran, M. and Padmanabhan, K. (2020) ‘A Fractographic Study of PE, PP Self-
reinforced Composites in Quasi-static Loading Conditions BT - Recent Advances in Mechanical
Engineering’, in Kumar, H. and Jain, P. K. (eds). Singapore: Springer Singapore, pp. 603–618.
5. Sharan Chandran M, Padmanabhan K; A Novel Correlative formulation of Interfacial, Quasi-
static and Dynamic Behaviour of Polyamide Self Reinforced Polymer Composites, Materials
today: proceeding, (Elsevier) (Article in Press).
6. Sharan Chandran, Yasaswi Chebiyyam, Padmanabhan K; Microbond multiple fibre pull-out test
to evaluate interface properties of UHMWPE/LDPE self reinforced polymer composites for
automotive applications, Journal of Engineering Research (Article in press)

59. Conference presentations
1. International conference on Materials and characterization
Techniques (ICMCT-2014) , VIT Vellore.
2. International conference of natural polymers(ICNP-2015)
MG University, Kottayam.
3. National Seminar on Aerospace Structures (NASAS-2017),
AR&DB, VIT Vellore.
4. National Conference on Advances in Mechanical
Engineering (NCAME-March 2019), NIT Delhi.
5. International conference in Mechanical engineering (IMEC-
Nov 29-Dec 1 2019), NIT Trichy.

60. References
1. Capiati N. J., Porter R. S.: Concept of one polymer composites modelled with high-density polyethylene.
Journal of Materials Science, 1975, 10, pages 1671-1677.
2. Pejis t.; Composites for recyclability, Materials Today, 6(4) 2003, pages 30-35
3. Alcock B, Pejis T, Technology and development of self-reinforced polymer composites, Adv. Polymer
Sci.,251,2013,1-76.
4. Case study : Light weight Self-reinforced Plastics for Ultimate Recyclability, Queen Mary University of
London.
5. Kmetty A et al.; Self reinforced polymeric materials: A review. Prog Polym Sci 2010; 35: 1288-310.
6. Matabola PK et al.; Single polymer composites: A review; J mater sci; 1975;10:1671-7
7. C. Gao et al.; Development of self-reinforced polymer composites; progress in polymer science 37 2012, 767-
780.
8. Deng M, Shalaby SW. Properties of self reinforced UHMWPE composites, Biomaterials 1997; 18:645-55.
9. Guan Q et el. Morphology and properties of HDPE SRC in oscillating stress field.polymer 1997, 38:5251-3
10. Huang HX,continuous extrusionof self reinforced HDPE,polymer science,Polymer engg science,
1998;38;1805-11
11. Zhang G et el, Self reinforced HDPE prepared by OPIM under low pressure, J applied polymer science, 1999,
71, 799-804.
12. Amer MS,Ganapathiraju S. Effects of processing parameters on axial stiffness of self-reinforced polyethylene
composites. J Appl Polym Sci 2001;81:1136-41.
13. B. Miller, U. Gaur, and D. E. Hirt, “Measurement and mechanical aspects of the microbond pull-out
technique for obtaining fiber/resin interfacial shear strength,” Compos. Sci. Technol., vol. 42, no. 1–3, pp.
207–219, 1991.
14. Padmanabhan Krishnan,, Bull.Materi.Sci,vol 40, No.4, AUGUST 2017, pp 737-744.
15. C.Y. Yue, K. Padmanabhan: Interfacial studies on surface modified Kevlar fibre/epoxy matrix composites.
60

61. 16. Yao, D., Li, R. and Nagarajan, P, Single-Polymer Composites Based on Slowly Crystallizing Polymers.
Polymer Engineering and Science,2006, pp. 1223-1230.
17. C. Schneider a, S. Kazemahvazi a,b, M. Åkermo a, D. Zenkert a; Compression and tensile properties of self-
reinforced poly(ethylene terephthalate)-composites; Polymer Testing 32 (2013) 221–230.
18. Chengcheng Gaoa, Long Yua,b, Hongsheng Liua, Ling Chena; Development of self-reinforced polymer
composites; Progress in Polymer Science 37 (2012) 767– 780.
19. V. Rao, P. Herrera-franco, A. D. Ozzello, L. T. Drzal: A Direct Comparison of the Fragmentation Test and the
Microbond Pull-out Test for Determining the Interfacial Shear Strength, 1991 Volume 34, - Issue 1-4,Page 65-67.
20. Amer MS, Ganapathiraju S. Effects of processing parameters on axial stiffness of self-reinforced polyethylene
composites. J Appl Polym Sci2001;81:1136–41.
21. Nagarajan, P. and Yao, D, 2005. Homocomposites of Poly(Ethylene Terephthalate), ANTEC, 2005, pp1559-
1563.
22. S Ramanathan, Kishore; Drop weight repeated impacts and post impact ILSS tests on glass epoxy composites;
proceedings of ICCM-10; whistler BC; Canada, August 1995.
23. S. Boria, A. Scattina , G. Belingardi : Impact behavior of a fully thermoplastic composite, Composite Structures
167 (2017) 63–75..
24. A. K. Bandaru, S. Patel, Y. Sachan, R. Alagirusamy, N. Bhatnagar, and S. Ahmad, “Low velocity impact
response of 3D angle-interlock Kevlar/basalt reinforced polypropylene composites,” Mater. Des., vol. 105, pp. 323–
332, 2016.
25. ASTM D5628-96. Standard test method for impact resistance of flat, rigid plastic specimens by means of a
falling dart (tup or falling mass).
26. Celal Evci, Mufit GulGec; An experimental investigation on the impact response of composite materials;
International Journal of impact engineering; 43; (2012) 40-51.
27. G. Simeoli, D Acierno, C. Meola, L. Sorrentino, S. lannace, P. Russo ;The role of interface strength on the low
velocity impact behavior of PP/glass fibre laminates; Composites: Part B; 62 (2014) 88-96.
28. C. Thanomsilp, P.J. Hogg; Composites Science and Technology 63 (2003) 467–482.
29. Ercan Sevkat, Benjamin Liaw, Feridum Delale, basavaraju B Raju; Drop weight impact of plain-woven hybrid
glass-graphite/toughened epoxy composites; Composites: Part A; 40(2009), 1090-1110.
61

62. References for standards
30. Standard Test Method for Tensile Properties of Polymer Matrix Composite
Materials, Designation D 3039/D 3039M-95a, Published by ASTM, West
Conshohocken, PA. 5.
31. Standard Test Methods for Flexural Properties of Unreinforced and Reinforced
Plastics and Electrical Insulating Materials, Designation D 790-03, Published by ASTM,
West Conshohocken, PA.
32. ASTM D5628-96. Standard test method for impact resistance of flat, rigid plastic
specimens by means of a falling dart (tup or falling weight).
62

63. Acknowledgements
I acknowledge
• VIT management,
• My guide Dr. K Padmanabhan
• Respected Thesis examiners,
• Dr. Dheepa Srinivasan, Dr. Velmurugan and Dr. Geetha Manivasagam
• SMEC Dean Dr. R Vasudevan,
• Former Deans Dr. S Senthil Kumar , Dr. S K Sekar and Dr. Arivazhagan,
• Design division HOD Dr. Mallikarjuna Reddy, former HODs Dr. Vasudevan and
Dr. Arun Tom Mathew
• Xavier sir of AMPT lab, staff of Machine shop, Ramya M Madam who was
project associate of Padmanabhan sir.
• Dr. Rajesh Kitey and Mr. C P Sharma of Structural Engg lab, Department of
Aerospace Engineering, IIT Kanpur.
• Dhvani R & D Solutions Pvt. Ltd for supporting in C-scan.
• SEM lab, SBST
• Analytical Chemistry lab in-charges and supporting staff for DSC,TGA and
FTIR
63

64. 64
नारायणायेति समर्पयातम !