Elastomeric fibers are fibers that can stretch to very high elongations (400-800%) and rapidly recover their original length. They include fibers made from natural and synthetic rubbers as well as spandex and polyacrylates. Elastomeric fibers are produced via a spinning process where polymers are mixed and reacted to form long chains, then extruded through spinnerets into a water bath or air to solidify. The fibers have excellent elasticity and strength even at high elongations. Common applications include clothing, automotive and industrial parts, coatings and more where elasticity is required.
Filament-core yarns are produced to take advantage of both filament and staple fibre properties. They offer good strength and uniformity without sacrificing the staple fibre yarn-like surface characteristics. Core-spun yarns containing spandex provide fabric designers with broad possibilities, because such stretchable yarns can be constructed with a wide range of properties using virtually any type of hard fibres as the cover yarn. However, a disadvantage of the core yarns is that the staple fibre sheath may slip along the filament when being pulled to pass over or when being rubbed by machine parts during further mechanical processes. But it is very easy to produce core-spun yarn containing spandex in a conventional ring frame after doing some modification of the machine.
Filament-core yarns are produced to take advantage of both filament and staple fibre properties. They offer good strength and uniformity without sacrificing the staple fibre yarn-like surface characteristics. Core-spun yarns containing spandex provide fabric designers with broad possibilities, because such stretchable yarns can be constructed with a wide range of properties using virtually any type of hard fibres as the cover yarn. However, a disadvantage of the core yarns is that the staple fibre sheath may slip along the filament when being pulled to pass over or when being rubbed by machine parts during further mechanical processes. But it is very easy to produce core-spun yarn containing spandex in a conventional ring frame after doing some modification of the machine.
DEFINITION: Pigment is a substrate in a particulate form which is insoluble in water but which can be dispersed in this medium to modify its color and light scattering properties. They are organic or inorganic coloring materials. They have no affinity to textile materials. They are fixed on the textile material with the help of binding agent in form a thin invisible coating.
2 Pre treatments of textile material.pptROHIT SINGH
The basic objective of pretreatment processing is removal of added or natural impurities present in textile fibres to improve the absorbency.
BY:ROHIT SINGH
to overcome the problem of easily fire catching to fabrics
it will reduce the wealth loss and causing material saving as well as it will cause healthy environment without sudden damage due to fire
chemicals treated are chlorine bromine , and also the bad effects of flame retardants
elastomeric fibers: properties and applicationsSeble Petros
elastomeric fibers are fibers which have a property of extreme extencibility and elastic recovery. this seminar describes major properties and applications of elastomeric fibers.
DEFINITION: Pigment is a substrate in a particulate form which is insoluble in water but which can be dispersed in this medium to modify its color and light scattering properties. They are organic or inorganic coloring materials. They have no affinity to textile materials. They are fixed on the textile material with the help of binding agent in form a thin invisible coating.
2 Pre treatments of textile material.pptROHIT SINGH
The basic objective of pretreatment processing is removal of added or natural impurities present in textile fibres to improve the absorbency.
BY:ROHIT SINGH
to overcome the problem of easily fire catching to fabrics
it will reduce the wealth loss and causing material saving as well as it will cause healthy environment without sudden damage due to fire
chemicals treated are chlorine bromine , and also the bad effects of flame retardants
elastomeric fibers: properties and applicationsSeble Petros
elastomeric fibers are fibers which have a property of extreme extencibility and elastic recovery. this seminar describes major properties and applications of elastomeric fibers.
Color fastness is one of the important factors in case of buyers demand. The outstandingly important property of a dyed material is the fastness of the shade of color. Color fastness refers to the resistance of color to fade or bleed of a dyed or printed textile materials to various types of influences e.g. water, light, rubbing, washing, perspiration etc. to which they are normally exposed in textile manufacturing and in daily use. We have written a lot of articles on color fastness.
As we know polyester is a synthetic fiber and has
more crystalline structure than natural fibers. In continuous
dyeing of polyester by pad-Thermosol process, there are many
advantages such as bulk production, low-cost, good efficiency etc.
But during dyeing process there is a severe problem occurs that
is dye migration .in order to control the dye migration different
migration inhibitors are used in this project. Both natural and
synthetic migration inhibitors are applied on the 100% polyester
fabric in order to compare that which migration inhibitor hives
better results on the pad-Thermosol process.
After comparing the different properties of the both migration
inhibitors the synthetic inhibitors found more efficient then the
natural one. The following tests were conducted during project:
Migration test, tensile strength, color strength, bending length,
light fatness.
Synthetic migration inhibitors gives better results for the tests
which were conducted .but there is a problem that the synthetic
migration inhibitors are not environmental friendly and they are
costly then natural migration inhibitors.
Preparation and characterisation of alumina nanocomposites with aramid fibre ...eSAT Journals
Abstract
The requirement of light weight and high strength materials are ever increasing in the industry. Lot of research is going on worldwide for improvement of mechanical properties of light weight non-metallic composites. Researchers are trying to meet the industrial requirements by modifying properties of composite materials by making nanocomposites. Nanocomposites are formed by mixing two or more dissimilar materials and adding nanoparticles in order to control and develop new and improved materials and their properties. The properties of composites depend not only upon the individual components used but also upon the morphology and the interfacial characteristics of the ingredients. This novel feature forms the basis of hypothesis to be investigated.
In the investigation for high strength materials, laminates of epoxy resin and nanoparticles of Al2O3 as filler are used with Aramid fibre, hybrid of carbon and aramid fibre as reinforcement are produced. Nanoparticles of Al2O3 of 20-30nm size are first dispersed in methanol by mechanical stirring. The solution is further sonicated for effective dispersion of nanoparticles. The mixture of methanol and Al2O3 nanoparticles are mixed in preheated Epoxy resin and mechanically stirred. During mixing some of the methanol is evaporated. Further, the remaining methanol is removed by heating and drying. Then, Hardener is mixed with the mixture of epoxy- Al2O3 and laminates are prepared. The laminates are cut to the required size of test samples for mechanical tests. It is observed that the mechanical properties are improved with the addition of nanoparticles of Al2O3.
Keywords: nanocomposites, bath sonication, Al2O3 Nanoparticles
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
2. Elastomer :
An Elastomer is a polymer with the physical property
of elasticity. Elastomer is a term derived from elastic
polymer, which is often used interchangeably with the
term rubber. Each of the monomers which link to from
the polymer is usually made of carbon, hydrogen,
oxygen and/or silicon. Elastomers are usually
thermosets requiring a curing process of rubber
involving heat and the addition of sulfur or other
equivalent curatives. In addition elastomers might also
be thermoplastic.
3. Elastomeric Fibers
Elastomeric fibers are those fibers that possess
extremely high elongations (400%-8001) at break and
that recover fully and rapidly from high elongations up
to their breaking point. Elastomeric fibers include the
crosslinked natural and synthetic rubbers, spandex
fibers (segmented polyurethanes), anidex fibers
(crosslinked polyacrylates) and the side-by-side
biconstituent fiber of nylon and spandex (Monvelle).
5. The spinning Process
When the two types of pre-polymers are mixed
together, they interact to form the spandex fibers. In
this reaction, the hydroxyl groups (-OH) on the macro
glycols react with the isocyanides. Each molecule gets
added on to the end of another molecule, and a long
chain polymer is formed. This is known as a step-
growth or addition polymerization. To initiate this
reaction, a catalyst such as diazobicyclo octane must
be used. Other low molecular weight amines are added
to control the molecular weight of the fibers.
7. Physical properties of elastomeric
fiber (spandex)
Tenacity : 037gm/den
Density : 1.21-1.35
Elongation at break : 400-700%
Elasticity : Excellent
Moisture regain : 0.6%
Resiliency : Very good
Ability to protest friction : Excellent
Color : White or near white
Luster : Less bright
8. Chemical properties of
elastomeric fiber
Acids : It has preventive power against all of the acidic
action.
Basic : Hot alkali damages the spandex filament.
Effect of bleaching : Bleaching agent damages the fibre and
it becomes weak.
Protection ability organic solvent : Good.
Protection ability light : Very good
Protection ability against mildew : Good
Protection ability against insects : It doesn’t affected by
insect.
Dyes : Disperse dyes , acid dye is suitable to dye spandex
filament,
9. Preparation of the elastomeric fibers
The preparation process of the elastomeric fibers is
illustrated in Fig.3. Firstly, the prepared spinning
dopes were stored in a container with piston and
pressed very slowly into a artificial duct (about
500 μm in inner diameter, and about 12 cm in
length). Secondly, the spinning dopes went
through the duct and flowed into the pure tap-
water in a glass water tank, immediately
solidifying and spontaneously rising to form the
initial fibers.
11. Thirdly, after the initial fibers freely rose from
underwater to water surface and stayed for about 3 min
in the tap-water, they were taken out of the water tank
and received vertical stretching up to 5–6 times of the
initial length in another water tank full of tap-water or
air, and after the vertical stretching was kept for about
40 min, the stretched fibers were prepared. Fourthly,
the stretched fibers were placed in a vacuum oven to
be dried for about 12 h at 45 °C under vacuum, and the
final fibers were produced. After the initial helical
fibers were taken out of the tap-water, they were
directly dried in the same conditions without vertical
stretching, and the final helical fibers were also made.
12. Various other types of elastomers:
Thermoplastic elastomers (TPE)
The proteins resilin and elastin
Polysulfide rubber
Elastolefin, elastic fiber used in fabric productio
13. Application of elastomeric fiber
1.Apparel
Athletic apparel , swimwear, underwear ,lingerie, foundation
garment, hosiery ,normal
clothing,belts,skipanty,slacks,socks,tubular knit fabrics for
ladies, and, warp knit fabrics for ladies, warp knit fabrics for
corsetry and sundry applications
2.Automotive
Body fasteners, electrical boots, suspension system parts, seals
and gaskets, belts, taillight assemblies, battery covers, hoses,
covers for electronics, adhesives, bushings, bump stops,
interlayer for laminates, air bag covers,transmission boots.
3.Adhesives and Sealants
Shoes, laminated security glazing, aerospace, marine, magnetic
media binders, construction.
15. Polyethylene Fiber
A manufactured fiber made of polymerized
polyethylene units. It is often a monofilament, but
is also available as continuous filament yarns and
as staple fiber. Polyethylene is a polymer. Many no.
of ethylene monomers join with each in the
synthesis of polyethylene polymer. Polyethylene
yarn cannot be dyed. It is colored by the addition
of pigments and dyes to the melt at extrusion.
Polyethylene can be created in several different
forms.
17. Chemical composition and molecular structure:
Ethylene (C2H4) is a gaseous hydrocarbon commonly
produced by the cracking of ethane, which in turn is a
major constituent of natural gas or can be distilled
from petroleum. Ethylene molecules are essentially
composed of two methylene units (CH2) linked together by
a double bond between the carbon atoms—a structure
represented by the formula CH2=CH2. Under the influence
of polymerization catalysts, the double bond can be broken
and the resultant extra single bond used to link to a carbon
atom in another ethylene molecule. Thus, made into the
repeating unit of a large, polymeric (multiple-unit)
molecule, ethylene has the following chemical structure: .
19. Spinning process of polyethylene fiber
Spinning of polyethylene is carried out by
melt spinning. The polymer with a
molecular weight of about 15,000 is spun
from the melt at about 205 deg C and
extended through a spinnerets of 0.1 mm
diameter into a current of cooling gas. The
filaments are cooled to 15 -60 deg C and
stretched 4 to 10 times their original length.
The drawn monofilaments are wound on
spools
21. Properties of Polyethylene Fiber
1. Polyethylene fibre has a round cross section and has a smooth
surface. Fibres made from low molecular weight polyethylene
have a grease like handle.
2. The moisture regain of polyethylene is practically nil and
hence moisture does not affect the mechanical properties of the
fibres.
3. Higher energy is needed to break because of specific modulus
and high specific strength
4. Polyethylene is insoluble in most of the common organic
solvents at room temperature.
5. Polyethylene fibres have a high degree of resistance to acids
and alkalies at all concentrations even at high temperature.
22. 6. Very good ultra violet resistance
7. The fibre is generally inert and is resistant to wide range of
chemicals at ordinary temperatures. They are attacked by
oxidising agents.
8. Excellent electrical and chemical resistance
9. Very good abrasion resistance
10. Other Properties
•Specific Gravity- 0.92
•Tenacity - 1.0-1.5 gpd
•Elongation at Break %- 45-50
•Tensile Strength psi - 15000
•Softening Range: deg C- 85-90
23. Application of Polyethylene
Medical implants
Cable and marine ropes
Sail cloth
Composites like Pressure vessel boat hulls, sports equipment,
impact shields
Fish netting
Concrete reinforcement
Protective clothing
Can be used in radar protective cover because of its low dielectric
constant
Can be used as a lining material of a pond which collects
evaporation of water and containment from industrial plants
Useful in geotextile applications
24. Conclusion
The preparation of a nanofiber membrane of an elastomer was
successful using the electrospinning process. The diameter of the
fiber is dependent significantly on solution concentration, voltage,
distance and the viscosity of the polymer. Beadless nanofiber
membrane that consisted of polybutadiene was obtained under the
condition of 5.25wt%, 25KV, and 5cm. The mean diameter of the
fiber was 0.46 µm. In addition, it was found that fibers without
beads were obtained by growing the multi-cone in the needle tip. It
was possible to co-electrospin VGCF or VGNF with the elasotomer.
The viscosity and electrical conductivity of the polymer increased
with the addition of VGCF/VGNF. The tensile strength of the
elastomeric nanofiber membrane was similar to that of the film.
However, the initial elastic modulus was very low. A soft feeling
elastomer nonwoven membrane was obtained