Polymers in daily life

POLYMERS IN DAILY LIFE

BY VIGNESH PRABHU.T

SCHOOL OF SCIENCE AND HUMANITIES KONGU ENGINEERING COLLEGE

(AUTONOMUS) PERUNDURAI-638052.

CONTENT

What is a Polymer ? Classification Poly lactic acid

Preparation Properties Applications Degradation Drawbacks Benefits Future works

WHAT IS A POLYMER ? Polymers are substances whose molecules

have high molar masses and are composed of a large number of repeating units. There are both naturally occurring and synthetic polymers. Among naturally occurring polymers are proteins, starches, cellulose, and latex.

Polymers are studied in the fields of biophysics and macromolecular science, and polymer science which includes

 polymer chemistry and polymer physics.

SOME COMMON EXAMPLES OF SYNTHETIC POLYMERS POLY ETHYLENE Polyethylene or polyethene is the most commonPlastic Its primary use is in packaging. Melting point: 115–135 °C Density: 0.91–0.96 g/cm3

Chemical formula: (C2H4)n

o POLY PROPYLENE Polypropylene is a thermoplastic polymer used in a wide variety of applications

including packaging and labeling, textiles, stationery, plastic parts and reusable containers.

Density: 946 kg/m³ Melting point: 130 °C Formula: (C3H6)n

POLY VINYL CHLORIDE Polyvinyl chloride, more correctly but unusually

poly(vinyl chloride), commonly abbreviated PVC, is the third-most widely produced synthetic plastic polymer

Density[g/cm3] :1.3–1.45 Chemical formula: (C2H3Cl)n Melting point :100–260 °C

NYLON Nylon is a generic designation for a family of synthetic polymers, more specifically aliphatic or semi-aromatic polyamides. They can be melt-processed into fibers, films or shapes.

o BAKELLITE Bakellite first plastics made from synthetic components, Bakelite was used for its electrical nonconductivity and heat-resistant properties in electrical insulators, radio and telephone casings, and such diverse products as kitchenware, jewelry, pipe stems, children's toys, and firearms.

POLY LACTIC ACID Polylactic acid (PLA) is a rigid thermoplastic

polymer that can be semicrystalline or totally amorphous, depending on the stereopurity of the polymer backbone.

Highly versatile thermoplastic material Made from 100% renewable resources PRODUCTION SOLVENT METHOD NON SOLVENT METHOD

SOLVENT METHODProducers have several industrial routes to

usable (i.e. high molecular weight) PLA. Two main monomers are used: lactic acid, and the cyclic di-ester, lactide.

NON SOLVENT METHOD Start with starch from renewable resource Renewable resources used : corn starch ,

tapioca roots, chips or sugarcane. Unrefined dextrose processed from starch Dextrose fermented into lactic acid Lactide produced through condensation Purification through vacuum distillation

PROPERTIES: PLLA has a crystallinity of around 37%,

a glass transition temperature 60–65 °C, a melting temperature  130°–230°C and a tensile modulus 2.7–16 GPa.

 Heat-resistant PLA can withstand temperatures of 110 °C.

 It is upto 7 times recycleable.

PROPERTIES(CONT’) Below Tg, PLA behaves as a glass with the

ability to creep until cooled to its transition temperature of approximately _45°C.

Below this temperature PLA will only behave as a brittle polymer.

 Polylactic acid can be processed like most thermoplastics into fiber (for example, using conventional melt spinning processes) and film

APPLICATIONS In agriculture : Coating of seeds can be done with the help of

poly lactic acid Prevents the seeds from damage during

transportation and sowing Withstands mechanical pressure When sown into the soil this PLA coating gets degraded easily Food products too can be coated with PLA which gets degraded easily

In medicine : Being able to degrade into

innocuous lactic acid, PLA is used as medical implants in the form of anchors, screws, plates, pins, rods, and as a mesh.

Depending on the exact type used, it breaks down inside the body within 6 months to 2 years.

This gradual degradation is desirable for a support structure, because it gradually transfers the load to the body (e.g. the bone) as that area heals.

PLA is also used in cosmetics

In industrial field : PLA can also be used as a decomposable

packaging material, either cast, injection-molded, or spun. 

Cups and bags have been made from this material.

In the form of a film, it shrinks upon heating, allowing it to be used in shrink tunnels.

It is useful for producing loose-fill packaging, compost bags, food packaging, and disposable tableware.

In the form of fibers and non-woven textiles, PLA also has many potential uses, for example as upholstery, disposable garments.

DEGRADATION Fully combustible in

composting facilities Can be converted back

to monomer Can be completely

broken down to H20, CO2, and organics

Degradation time: weeks to months

DRAWBACKS PLA releases carbon dioxide and methane

during the biological breakdown phase Fossil fuels still needed to produce PLA Some believe that PLA will degrade too

slowly to make a difference in waste streams

BENEFITS Biodegradable: Less

landfill space! 1500 pounds of waste

per year for every person

Plastic materials account for 20% (vol.) of landfills

20-50% less fossil fuels used in production than in petroleum based polymers

No net increase in CO2

emissions

FUTURE WORKS

THANK YOU