Association of Polymer Tech. Engineering NAU, Onitsha (2026)

23/01/2018

Polymers and food
Polymers are used very widely in the production, distribution, packaging and
preparation of food. some examples of such uses are listed below.
Farming:
■ Sheeting to protect crops
■ Encapsulation of seeds (gels and nutrients)
■ Protective clothing for farm workers.
Distribution:
■ Packaging in an inert atmosphere
■ Vacuum packing
■ Insulated packaging.
Retail:
■ Carrier bags (now biodegradable)
■ A variety of packaging types
■ Display units.
In the kitchen:
■ Storage (sealable containers, cling film, vacuum packing machines)
■ Food preparation (plastic cutting boards, microwave-safe transparent containers,
flexible utensils, cook-in-the-bag techniques).
In food
■ Swelling of starch – perfect chips, roast potatoes, risotto.
■ Denaturation of protein and connective tissue – cooking meat at low temperature.
■ Thickening of soup using starch, gelatine (a heteropolymer of amino acids) or
insulin (a non-digestible polysaccharide).

31/08/2017

The Science Behind 4 Of The Greatest Polymers Of All Time
Just because something is old doesn’t mean it isn’t still awesome!
By Martha Harbison November 15, 2012

MILITARY TROOPS IN NOMEX GEAR DURING THE YELLOWSTONE FIRES OF 1988
Jim Peaco via Wikimedia Commons
Here at PopSci, we usually focus on the newest innovations in science and technology. But many past innovations in polymer science--the study of plastics and other similar materials--are still relevant and deserve recognition. They've saved lives, kept babies dry and made huge shark observation tanks possible. Some have tradenames that have gone on to represent an entire class of product, such as Kevlar. Others lurk in obscurity. Here are some of the most important materials and a glimpse into how scientists designed them to work their magic.
PMMA

Applications: Lucite, dentures, aquarium windows
Developed in: 1877

Polymethylmethacrylate is a very versatile polymer. If you ever see a clear plastic block, it's probably PMMA. It was first commercialized in the 1930s in Germany, and is now found anywhere one needs clear, strong material. This includes bulletproof "glass" at your favorite corner liquor store and the huge shark tanks at the Monterey Bay Aquarium. But my favorite use of PMMA is in so-called "frozen lightning" or Lichtenberg figure sculpture. Basically, put a chunk of PMMA into an electron accelerator, fire a bunch of electrons into the plastic until it's got about two million volts of charge, then touch the side of the plastic with a bit of wire and watch as bolts of lightning carve tracks inside the clear plastic.
Click for video
Superabsorbers

Applications: Diapers
Developed in: 1960s
Back in the day, diapers were made from cloth. Frequently, those cloth diapers were filled with wads of natural absorbent fibers. Then polymer scientists discovered in the 1960s that they could make hydrogels like polyacrylic acid that absorb many times their own weight of water. It took about two decades, but polymer superabsorbers debuted in diapers in the mid-'80s. Superabsorbers are sometimes (but not always) polyelectrolytes, meaning that the side groups on the polymer chains are positively or negatively charged. That helps the chains associate with polar liquids like water.
Click for video
Kevlar and Nomex

Applications: Bulletproof vests and fireproof clothing, respectively
Developed in: early 1960s (Nomex); 1965 (Kevlar)
Kevlar and Nomex are two polymers that belong to a class of compounds called aramids--aromatic polyamides. Aramids have particularly strong chemical bonds, and materials scientist exploit that strength when creating impact and fire-resistant fibers from the polymers. For example, Kevlar fibers are especially strong because all of the polymer chains align, one right next to the other, during fiber spinning. Nomex has a slight kink in the polymer chain, which means that fibers made from it cannot line up perfectly, and thus will be slightly weaker. Both are relatively fire-resistant, but Kevlar's strength can stop bullets. In addition to bulletproof vests, Kevlar shows up in snare drum heads. Nomex is used in fire-fighters' protective gear.
Click for video
Click for video
Polystyrene

Application: Shrinky D***s
Developed in: 1839
Shrinky D***s are awesome. Color some strips of plastic, pop 'em in the oven and watch them fold up onto themselves. It turns out that these rainy day items are made from the same polymer as Styrofoam cups: polystyrene. Polystyrene, which was first commercialized in Germany in 1931 (styrofoam wasn't developed until 1954 in the United States), is a very versatile polymer and millions of tons of it are produced annually. A Shrinky D**k starts out as a sheet of polystyrene that has been pressed and flattened while close to the melting point. This forces the polymer chains to stretch out and line up. The sheet cools and the polymer chains are frozen into place (think of it as stretching out a Slinky and holding it). When you throw a Shrinky D**k in the oven, the polymer sheet warms up, and the polymer chains start to move around. When hot enough, all of the polymer chains coil back up, making the sheet of polymer shrink, just like a Slinky will pull itself together when you let go. Scientists at Northwestern University recently took advantage of that property to create nanopatterned surfaces. To get structures really, really close together, they used the stretched polystyrene and printed dots on the surface. Then they heated up the sheet, which shrunk, creating a very high-density array of dots.

31/08/2017

Polymers are everywhere and play a vital role in our everyday lives. Highly engineered multilayer polymer films are used in food packaging to ensure freshness. High strength polymer fibers are used in seat belts keeping us safe in the event of a crash. We rely on plastic containers of all types in our everyday lives. Need to fix a broken part? You can use ultra fast curing Crazy Glue (cyanoacrylates) or go down to Home Depot and pick up a two part 5 minute epoxy. These types of polymers are formed during curing and have unique properties due to their crosslinked network structure. Did you know that most semiconductor chips in your iPhone or computer are actually glued to either a metal or polymer substrate using sophisticated adhesives that are electrically conductive? Reactive chemistries (epoxy, acrylate, bismaleimide and others) are widely used in adhesives since they start as small molecules (easy to dispense) and on curing react into a solid, high strength adhesive. Recently I visited my father-in-law’s farm in central Illinois. Big Sky Wind, LLC is constructing a wind farm with 114 turbines. Two will be on his farm. I got a close look at the blades. Amazing. There are three blades per turbine and are 142 feet long. What are they made of? You guessed it, polymer composites. In this case, the polymers are not used alone, but are mixed with reinforcing glass cloth to form a fiberglass composite. I will have more on wind turbine blade production in a subsequent post. The new Boeing Dreamliner 787 is the first commercial airplane to have a composite fuselage.

So where did this all start? Wallace H. Carothers was an incredibly talented chemist at DuPont Chemical in the early 1930’s. He is largely responsible for what is the polymer industry today and is credited with the invention of neoprene and nylon. Carothers invented neoprene in 1931 and nylon in 1934. It was the invention of nylon and the subsequent breakthrough in making nylon fiber that revolutionized the industry. Carothers and his team at DuPont developed the polymerization and fiber spinning process enabling the production of highly oriented nylon fibers with more elasticity and high strength. Nylon fibers where then used to make a wide variety of fabrics. Nylon was an instant best seller in 1940 when DuPont began making women’s “nylons.” The rest as they say “is history.” Nylon became very important during the Second World War. The military used it in 3.8 million parachutes, a half a million air plane tires, uncounted numbers of glider tow ropes, flask vests, and blood plasma filters.

After the World War II, the advances in polymer science accelerated at an amazing pace. You might not have realized this, but the synthetic polymer industry is relatively young compared to ceramics and metal uses going back several thousand years. In subsequent posts, we will explore the role of innovation in polymers and highlight some current new applications and trends.

31/08/2017

Biopolymers
Definition
Biopolymers are polymers synthesized by living organisms. Biopolymers can be polynucleotides (such as the nucleic acids DNA and RNA), polypeptides (that is, proteins) or polysaccharides (that is, polymeric carbohydrates).These consist of long chains made of repeating, covalently bonded units, such as nucleotides, amino acids or monosaccharides.

07/11/2016

POLYMERS

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. Synthetic polymers are produced commercially on a very large scale and have a wide range of properties and uses. The materials commonly called plastics are all synthetic polymers.

Polymers are formed by chemical reactions in which a large number of molecules called monomers are joined sequentially, forming a chain. In many polymers, only one monomer is used. In others, two or three different monomers may be combined. Polymers are classified by the characteristics of the reactions by which they are formed. If all atoms in the monomers are incorporated into the polymer, the polymer is called an addition polymer. If some of the atoms of the monomers are released into small molecules, such as water, the polymer is called a condensation polymer. Most addition polymers are made from monomers containing a double bond between carbon atoms. Such monomers are called olefins, and most commercial addition polymers are polyolefins. Condensation polymers are made from monomers that have two different groups of atoms which can join together to form, for example, ester or amide links. Polyesters are an important class of commercial polymers, as are polyamides (nylon).

21/07/2016

Modification of natural polymers
Naturally occurring polymers such as cotton,
starch and rubber were familiar materials for
years before synthetic polymers such as
polyethene and perspex appeared on the
market. Many commercially important
polymers are synthesized by chemical
modification of naturally occurring polymers.
Prominent examples include the reaction of
nitric acid and cellulose to form nitrocellulose
and the formation of vulcanized rubber by
heating natural rubber in the presence of
sulfur . Ways in which polymers can be
modified include oxidation , cross-linking and
end-capping.
Especially in the production of polymers, the
gas separation by membranes has acquired
increasing importance in the petrochemical
industry and is now a relatively well-
established unit operation. The process of
polymer degassing is necessary to suit
polymer for extrusion and pelletizing,
increasing safety, environmental, and product
quality aspects. Nitrogen is generally used for
this purpose, resulting in a vent gas primarily
composed of monomers and nitrogen.

06/06/2016

Organic polymers
The eight most common types of synthetic
organic polymers, which are commonly found
in households are:
Low Density Polyethylene (LDPE),
High Density Polyethylene (HDPE),
Polypropylene (PP)
Polyvinyl Chloride (PVC)
Polystyrene (PS)
Nylon, nylon 6, nylon 6,6
Teflon (Polytetrafluoroethylene)
Thermoplastic polyurethanes (TPU)

06/06/2016

IUPAC definition
List of synthetic
polymers
Synthetic polymers are human-made
polymers. From the utility point of view they
can be classified into four main categories:
thermoplastics , thermosets , elastomers and
synthetic fibers . They are found commonly in a
variety of consumer products such as money,
super glue, etc.
A wide variety of synthetic polymers are
available with variations in main chain as well
as side chains. The back bones of common
synthetic polymers such as polythene,
polystyrene and poly acrylates are made up of
carbon-carbon bonds, whereas hetero chain
polymers such as polyamides, polyesters,
polyurethanes, polysulfides and polycarbonates
have other elements (e.g. oxygen, sulfur,
nitrogen) inserted along the backbone. Also
silicon forms similar materials without the
need of carbon atoms, such as silicones
through siloxane linkages; these compounds
are thus said to be inorganic polymers.
Coordination polymers may contain a range of
metals in the backbone, with non-covalent
bonding present.
Some familiar household synthetic polymers
include: Nylons in textiles and fabrics, Teflon in
non-stick pans, Bakelite for electrical switches,
polyvinyl chloride (PVC) in pipes, etc. The
common PET bottles are made of a synthetic
polymer, polyethylene terephthalate. The
plastic kits and covers are mostly made of
synthetic polymers like polythene and tires are
manufactured from Buna rubbers.[1] However,
due to the environmental issues created by
these synthetic polymers which are mostly
non-biodegradable and often synthesized from
petroleum, alternatives like bioplastics are also
being considered. They are however expensive
when compared to the synthetic polymers.

06/06/2016

A polymer (/ˈpɒlᵻmər/; Greek
poly-, "many" + -mer,
"parts") is a large molecule,
or macromolecule, composed
of many repeated subunits.
Because of their broad range
of properties, both synthetic
and natural polymers play an essential and
ubiquitous role in everyday life.

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