Polymers can be formed through addition polymerization or step-growth polymerization. They have various molecular structures that influence properties like crystallinity. Thermoplastics soften when heated while thermosets form permanent chemical bonds. Common polymers include polyethylene, polypropylene, polystyrene, and nylon. They are processed through methods like extrusion, injection molding, and thermoforming to make a wide range of products.
Methods of polymerisation It is also called as Zeigler – Natta polymerisation.
Zeigler (1953) and Natta (1955) discovered that in the presence of a combination of transition metal halides like TCl4, ZnBr3 etc, with an organometallic compound like triethyl-aluminium or trimethyl-aluminium, stereospecific polymerisation can be carried out.
Combination of metal halides and organometallic compounds are called Zeigler Natta catalyst.
Methods of polymerisation It is also called as Zeigler – Natta polymerisation.
Zeigler (1953) and Natta (1955) discovered that in the presence of a combination of transition metal halides like TCl4, ZnBr3 etc, with an organometallic compound like triethyl-aluminium or trimethyl-aluminium, stereospecific polymerisation can be carried out.
Combination of metal halides and organometallic compounds are called Zeigler Natta catalyst.
Basic Terms : Macromolecule, Monomer , Repeat Unit, Classification of polymers based on Origin, thermal response Polymerisation , Addition and condensation , Degree of Polymerisation, Polymer Structures - Linear , Branched and Cross-linked. Molecular weight of Polymers: Definition and Formulae of Number Average Molecular Weight , Weight Average Molecular weight, Viscosity Average Molecular Weight , Z-average Molecular Weight. Polydispersity Index
All details about the dental polymer
Components and Composition
Molecular Weight
Polydispersity
Structure Of Polymer
Mechanical And Physical Properties Of Polymer,
Rheometric Properties
Solvation and dissolution Properties
Thermal Properties
Requirement Of Dental Resins
Dental Use Of Resins
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Basic Terms : Macromolecule, Monomer , Repeat Unit, Classification of polymers based on Origin, thermal response Polymerisation , Addition and condensation , Degree of Polymerisation, Polymer Structures - Linear , Branched and Cross-linked. Molecular weight of Polymers: Definition and Formulae of Number Average Molecular Weight , Weight Average Molecular weight, Viscosity Average Molecular Weight , Z-average Molecular Weight. Polydispersity Index
All details about the dental polymer
Components and Composition
Molecular Weight
Polydispersity
Structure Of Polymer
Mechanical And Physical Properties Of Polymer,
Rheometric Properties
Solvation and dissolution Properties
Thermal Properties
Requirement Of Dental Resins
Dental Use Of Resins
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
In my system we have to make a system by which a user can record all events coordinated by a particular faculty. In our proposed system some more featured are added which differs it from the existing system such as security.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
2. The Outline
Summery
Reactions of polymers
Addition Polymerization
Step Growth Polymerization
Chemical and Physical Structures of Polymers
Polymer’s molecular structures
Configuration and conformation of polymers
Chain structures of polymers
Physical Structures of Polymers
Polymer crystallinity
Crystallinity and amorphousness of polymers
3. The Outline
Summery
Types of Polymers and Polymer Processing
Members of Polymers
Definition of Thermosets & Thermoplastics
Common products and their properties
Forming Techniques of Polymers
Extrusion of polymers
Injection Molding
Blow Molding
Thermoforming
Compression Molding
Casting
4. A polymer is a large molecule made by linking together
repeating units of small molecules called monomers
7. Differences between step-growth polymerization and
chain-growth polymerization
Step-growth polymerization Chain-growth polymerization
Growth throughout matrix Growth by addition of monomer only at
one end of chain
Rapid loss of monomer early in the
reaction
Some monomer remains even at long
reaction times
Same mechanism throughout Different mechanisms operate at
different stages of reaction (i.e.
Initiation, propagation and
termination)
Average molecular weight increases
slowly at low conversion and high
extents of reaction are required to
obtain high chain length
Molar mass of backbone chain increases
rapidly at early stage and remains
approximately the same throughout the
polymerization
Ends remain active (no termination) Chains not active after termination
No initiator necessary Initiator required
13. IONIC CHAIN POLYMERIZATION
Using catalyst, not initiator
Highest reaction rate
Termination step is just disproportionation
Environment must be pure
Reaction occurs in the cold
14. Anionic Polymerization=Living Polymerization
If the starting reagents are pure and the
polimerization reactor is purged of all oxygen and
traces of water, polimerization can proceed until
all monomer is consumed.
15. CONDENSATION POLYMERIZATION
Using catalyst
Minumum two functional groups required
Usually linear
Molecular weight increases slowly at low conversion
High extents of reaction are required to obtain high
chain length
16. Chemical Structure of Polymers
Molecular configuration of polymers
Side groups atoms or molecules with free bonds, called free-radicals, like H, O,
methyl affects polymer properties.
Stereoregularity describes the configuration of polymer chains :
Isotactic is an arrangement where all substituents are on the same side of the
polymer chain.
Syndiotactic polymer chain is composed of alternating groups
Atactic the radical groups are positioned at random
Figure 2: Isotactic Syndiotactic and Atactic combinations of a stereoisomers of polymer chain
(http://www.microscopy-uk.org.uk/mag/imgsep07/atactic.png)
17. Molecular configuration of polymers
FIGURE.3. Diagrams of (a) isotactic, (b) syndiotactic, and (c) atactic configuration in a vinyl polymer.
The corresponding Fischer projections are shown on the right.
(Plastic Technolgoy Handbook)
18. Table 1. Properties of Polypropylene Stereoisomers
(Plastic Technology Handbook)
19. Molecular configuration of polymers
Geometrical isomerism:
The two types of polymer configurations are cis and trans. These structures
can not be changed by physical means (e.g. rotation).
The cis configuration → substituent groups are on the same side of a carbon-
carbon double bond.
Trans → the substituents on opposite sides of the double bond.
Figure4.cis trans configurations of polyisoprene
( http://openlearn.open.ac.uk/file.php/2937/T838_1_019i.jpg )
20. Conformations of a Polymer Molecule
Conformation →The two atoms have other atoms or groups attached
to them configurations which vary in torsional angle are known as
conformations (torsional angle:The rotation about a single bond which
joins two atoms )
Polymer molecule can take on many conformations.
Different conformation →different potential energies of the
molecule→Some conformations: Anti (Trans), Eclipsed (Cis), and Gauche (+
or -)
21. Other Chain Structures
Copolymers →polymers that incorporate more than one kind of
monomer into their chain (nylon)
Three important types of copolymers:
Random copolymer contains a random arrangement of the multiple
monomers.
Block copolymer contains blocks of monomers of the same type
Graft copolymer contains a main chain polymer consisting of one type
of monomer with branches made up of other monomers.
Figure 5 :Block Copolymer Graft Copolymer Random Copolymer
http://plc.cwru.edu/tutorial/enhanced/FILES/Polymers/struct/struct.htm
22. Physical Characteristics of Polymers
The melting or softening temperature ↑ molecular weight ↑
The molecular shape of the polymer has influence on the elastic
properties. ↑ coils the ↑ elasticity of the polymer
The structure of the molecular chains has an effect on the strength
and thermal stability. ↑ crosslink and network structure within the
molecule ↑ the strength and thermal stability.
23. Polymer Crystallinity
Crystallinity is indication of amount of crystalline region in polymer
with respect to amorphous content
X-ray scattering and electron microscopy have shown that the
crystallites are made up of lamellae which,in turn, are built-up of
folded polymer chains
Figure.6 Schematic representation of (a) fold plane showing regular chain folding, (b) ideal stacking oflamellar
crystals, (c) interlamellar amorphous model, and (d) fringed micelle model of randomly distributed crystallites
(Plastic Technology Handbook)
24. Polymer crystallinity
Crystallinity occurs when linear polymer chains are structurally
oriented in a uniform three dimensional matrix. Three factors that
influence the degree of crystallinity are:
i) Chain length
ii) Chain branching
iii) Interchain bonding
Figure 7: Crystalline chain
http://plc.cwru.edu/tutorial/enhanced/FILES/Polymers/orient/Orient.htm
25. Polymer cristallinity
Crystallinity influences:
Hardness,modulus tensile, stiffness, crease, melting point of polymers.
Most crystalline polymers are not entirely crystalline. The chains, or
parts of chains, that aren't in the crystals have no order to the
arrangement of their chains
Crystallinity makes a polymers strong, but also lowers their impact
resistance
Crystalline polymers are denser than amorphous polymers, so the
degree of crystallinity can be obtained from the measurement of
density → Wc=Φcρc/ ρ
ρ → density of entire sample
ρc → density of the crystalline fraction.
Φc→ volume fraction
Wc→ mass fraction
26. Determinants of Polymer Crystallinity
The degree of crystallinity of a polymer depends on the rate of cooling
during solidification as well as on the chain configuration.
In most polymers, the combination of crystalline and amorphous
structures forms a material with advantageous properties of strength
and stiffness.
Figure 8: Mixed amorphous crystalline macromolecular polymer structure
(http://web.utk.edu/~mse/Textiles/Polymer%20Crystallinity.htm)
27. Polymer cristallinity
Polymer molecules are very large so it might seem that they could not
pack together regularly and form a crystal. Regular polymers may form
lamellar crystals with parallel chains that are perpendicular to the face
of the crystals.
A crystalline polymer consists of the crystalline portion and the
amorphous portion. The crystalline portion is in the lamellae, and the
amorphous portion is outside the lamellae .
Figure 9. Arrangement of crystalline and amorphous portions
http://pslc.ws/mactest/crystal.htm#structure
28. Cristillanity and amorphousness
An amorphous solid is formed when the chains have little orientation
throughout the bulk polymer. The glass transition temperature is the point
at which the polymer hardens into an amorphous solid.
In between the crystalline lamellae,regions with no order to the
arrangement of the polymer chains → amorphous regions
Polyethylene can be crystalline or amorphous. Linear polyethylene is nearly
100% crystalline. But the branched polyethylene is highly amorphous.
Figure 10.Linear and Branched Polyethylene
(http://pslc.ws/macrog/kidsmac/images/pe03.gif )
29. Examples...
Highly crystalline polymers:
Polypropylene, Nylon, Syndiotactic polystyrene..
Highly amorphous polymers:
Polycarbonate, polyisoprene, polybutadiene
Polymer structure and intermolecular forces has a major role of a
polymer’s crystallinity.
30. Classification of Polymers
…with regard to their thermal processing behavior ;
Thermoplastic Polymers (Thermoplastics)
soften when heated and harden when cooled
Thermosetting Polymers (Thermosets)
once having formed won’t soften upon heating
32. have strong covalent bonds and weak intermolecular van
der Waals bonds
elastic and flexible above glass transition temperature
can be heat softened, remolded into different forms
reversible physical changes without a change in the
chemical structure
33. Thermosets
chains chemically linked by covalent bonds
hardening involves a chemical reaction which
connects the linear molecules together to form a
single macromolecule.
34. Thermosets
once polymerization is complete, cannot be softened, melted
or molded non-destructively.
have higher thermal, chemical and creep resistance than
thermoplastics
Thermosets suitable materials for
Composites
Coatings
Adhesive applications
36. POLYETHYLENE
prepared directly from the polymerization of ethylene (C2H4).
two main types are; low-density (LDPE) and high-density
polyethylene (HDPE)
Advantages
cheap
good chemical resistance
high impact strength
37. Limitations
low heat resistance (upper temperature limit is 60°)
degrade under UV irradiation.
high gas permeability, particularly CO2
Applications
extensively for piping and packaging
chemically resistant fittings, garbage bags
containers, cable covering
38. POLYPROPLYLENE
improved mechanical properties compared to polyethylene;
has a low density (900–915 kg/m3), harder, and has a higher
strength
Good chemical and fatigue resistance
Disadvantages
Oxidative degradation, high thermal expansion, high creep
poor UV resistance
Applications
medical components, films for packaging (e.g. cigarette
packets)reusable containers, laboratory equipment
39. POLYSTYRENE
a light amorphous thermoplastic
Advantages
low cost, easy to mould, rigid, transparent
no taste, odor, or toxicity, good electrical insulation
Disadvantages
sensitive to UV irradiation (e.g. sunlight exposure)
chemical resistance is poor, brittle
Applications
CD-DVD cases, electronic housings, food packaging, foam
drink cups and egg boxes
40. POLYVINYLCHLORIDE-PVC
was the first thermoplastic used in industrial applications
very resistant to strong mineral acid and bases, good electrical
insulators, flame-retardant
Two grades of the PVC material are available:
rigid PVC is used in the construction industry for piping
cold water and chemicals
flexible PVC is used in wire and cable coating, paints, signs
42. EPOXIES
Advantage
mechanically strong, highly adhesive
good chemical and heat resistance
electrical insulators
Disadvantage
expensive
Applications
as industrial adhesives, coatings or as matrices in advanced
reinforced plastics and also as encapsulation media
43. UNSATURATED POLYSTERS
Advantage
hard, high strength
cheap compared to Epoxy
good electrical insulator
high heat resistance
Disadvantage
poor solvent resistance compared to other thermosets
Applications
molding or casting materials for a variety of electrical
applications, matrix for composites such as fiberglass
boats, fences, helmets, auto body components
44. PHENOLICS
most commonly used thermosets
high hardness, excellent thermal stability; low
tendency to creep
Applications
wiring devices, bottle caps, automotive parts, plugs
and switches, as adhesives coatings and molded
components for electrical applications
45. POLYURETHANES
depending on the degree of cross-linking they behave as
thermosets or thermoplastics
low cost, high impact strength, high adhesion properties
be processed into coatings, adhesives, binders, fibers and
foams