1. Polyethylene, PE

Polyethylene, PE, is a semicrystalline thermoplastic polymer. Different production methods are used to produce particular qualities of macromolecular structure and density. The macromolecules of high density polyethylene, PE-HD, are practically unbranched. The degree of crystallinity is therefore high (60-80) and the density is about 0.95 g/㎤. Low-density polyethylene, PE-LD, is strongly branched and has a lower crystallinity (20 to 40%) and a density of about 0.92 g/㎤. In PE-LLD (linear low density) the crystallization is hindered by short side groups created by copolymerization with  -olefins, e.g. hexene to obtain a film of high strength combined with good transparency (important for packaging purposes).
PE is a nonpolar material with low water sorption. It is an excellent electrical insulator. Polyethylene after molding can be cross-linked to enhance dimensional stability.
Applications: films, cable insulation, water and gas pipes, bottles, containers, household appliances, nets, ropes.

Thermal analysis of PE:

DSC:    Characterization via melting behavior, crystallinity, oxidation stability.
TGA:    Degradation behavior, carbon black content, filler content.
TMA:    Expansion behavior, expansivity, degree of cross-linking.
DMA:    Modulus, viscoelastic and damping behavior, glass transition.

2. Ethylene/vinylacetate copolymer, E/VAC

These two monomers can be copolymerized in any ratio. With increasing VAC content, the material becomes softer and more transparent. The properties range from being semicrystalline thermoplastic to amorphous, rubber-like and good low temperature properties. E/VAC was the first commercially available thermoplastic elastomer (easily molded, properties almost like a vulcanized rubber).
Applications: soft tubes and hoses, films (bags for deep freezer), heat and weather resistant “rubber” ware, hot melt.

Thermal analysis of E/VAC:

DSC:    Characterization via glass transition (approx.-40℃) and melting range (from 40 to 100℃),  Oxidation stability.
TGA:    Thermal stability, degradation behavior, filler content.
TMA:    Glass transition, expansion behavior, expansivity, thermoplastic flowing.
DMA:    Modulus, viscoelastic and damping behavior, glass transition.

3. Polypropylene, pp

Regularly synthesized PP macromolecules result in a semicrystalline material. PP is harder and has a higher dimensional stability compared with PE. But it is prone to oxidation due to its methyl groups.
Applications: films, cable insulation, hot water pipes household appliances, parts of laboratory equipment and washing machines, ropes.  

Thermal analysis of PP:
DSC:    Characterization via meltihng  behavior, crystallinity, oxidation stability.
TGA:    Degradation bebavior, carbon black content, filler content.
TMA:    Expansion behavior, expansivity.
DMA:    Modulus, viscoelastic and damping behavior, glass transition.

4. Polystyrene, PS  

Polystyrene, PS, is  colorless, transparent, rigid and brittle. For better impact resistance copolymers and terpolymers are produced styrene-acrylonitrile copolymer: SAN(US and J: AS); styrene-butadiene copolymer: S/B, acrylonitrile-butadiene-styrene terpolymer: ABS］. SAN copolymers are transparent with a light yellowish tone, the surface of S/B is dull, ABS is opaque.

Applications of PS: cheap transparent mass products, customer gifts, one way beakers, toys, foamed PS for packaging and heat insulation.
High impact copolymers and terpolymers: inner linings of refrigerators., housings of vacuum cleaners, toys, satety helments, small boats.

Thermal analysis of polystyrene plastics:

DSC:    Characterization via glass transition (approx. 100℃, copolymer with butadiene in addition approx. 85℃, with acrylonitrile in addition (approx. 135℃), thermal stability (onset of depolymerization).
TGA:    Thermal stability, degradation behavior, filler content.
TMA:    Glass transitions, expansion behavior, expansivity, thermoplastic flowing.
DMA:    Modulus, viscoelastic and damping behavior, glass transition.  

5. Polyvinyl chloride, PVC  

PVC is amorphous, transparent (but frequently opaque due to fillers) and chemically stable. Further  Chlorination (PVCC) increases the glass temperature from approx. 80℃ to 100℃. On the other hand, it can be lowered to almost any value by the addition of plasticizers (PVC-S). The great disadvantage is thermal degradation, which begins around 180℃. The hydrochloric acid evolved is very corrosive.

Applications:
PVC-U: window frames, waste water pipes, undercoating of cars, instrument boards, acid containers, Sheeting.
PVC-S: pipes, toys, balls, films for roof sealing and swimming pools, imitation leather (<>).

Thermal analysis of PVC:

DSC:    Characterization via glass transition (approx.-40 to +90℃, depending on plasticizer content), thermal stability.
TGA:    Thermal stability, degradation behavior, filler content.
TMA:    Glass transition, expansion behavior, expansivity.
DMA:    Modulus, viscoelastic and damping behavior, glass transition, gelation.

6. Polyvinyl acetate, PVAC

PVAC is not used to make plastic parts: it is too soft. Commercially, the most important form of PVAC is as an emulsion in water. On drying, the dispersion forms a film that adheres well to all kinds of substrates.
Applications: PVAC is the binder in emulsion adhesives and paints. Plasticizers lower the glass transition temperature of about 40℃ still further.

Thermal analysis of PVAC:

DSC:    Characterization via glass transition (about 40℃), with plasticizer much lower.
TGA:    Thermal stability, degradation behavior, filler content.
TMA:    Glass transitions, expansion behavior, thermoplastic flow (cold flow).
DMA:    Modulus, viscoelastic and damping behavior, glass transition.

7. Polyamide, PA

Polyamides are semicrystalline thermoplastic polymers with excellent mechanical properties suce  as toughness and wear strength. Polyamides immersed in water or exposed to ambient air absorb several percent of moisture. Due to the high melting temperatures, dimensional stability at elevated temperatures is excellent. Polyamides are easy to mosify (copolymerization, mineral fillers, fiber reinforcement).

Application: gear wheels, belt pulleys, bearings, screws, fans, car parts, water taps, and fibers, which become especially strong through orientation on spinning.

Thermal analysis of PA:

DSC:  Identification of PA6, 66, 10, 11, 12 via melting peak temperature, crystallinity.
TGA:  Degradation behavior, filler content.
TMA:  Expansion and shrink behavior, expansivity.  
DMA:  Modulus, viscoelastic and damping behavior, glass transition.

8. Polyethylene terephthalate, PET    

Polythylene terephthalate, PET is a semicrystalline thermoplastic polymer that can be fozen in the amorphous state by shock-cooling from the molten state. The rate of growth of PET spherulites is about 500 times lower than with PE. This characteristic is applied in he cold crystallization of PET:
Amorphous sheets or films are thermoformed above the glass transition temperature and crystallize at the same time. The crystallization increases the heat distortion temperature (temperature at which the dimensional stability is lost) by more than 100 K. In this way cold crystallized PET become opaque.
Oriented films and fibers are transparent despite their high crystallinity.

Applications: Since 1950, PET has been used mainly for wear-and weather-resistant fibers for clothing, sails, and non-woven material (trade names, e.g.Dacron, Terylene, Trevira)and for dimensionally stable films of high tensile strength (for audio and videotapes, computer disks and graphical purposes).
Some technical parts, such as gear wheels, bearings and in the recent years soft drink bottles are made from PET.

Thermal analysis of PET:

DSC:    Indentification via glassm transition temperature, cold crystallization and melting peak temperature. Degree of crystallinity and the oxidation onset temperature are also important.
TGA:    Degradation behavior, thermal stability, filler content.
TMA:    Glass transition, cold crystallization, expansion behavior, expansivity, thermoplastic flow.
DMA:    Modulus, viscoelastic and damping behavior, glass transition.

9. Polycarbonate, PC

Polycarbonate, PC, is an amorphous transparent material of high strength and high impact strength. It has a high heat distortion temperature.

Applications of PC: technical parts that are exposed to elevated temperatures (e.g. sterilizable bottles)
Compact disks, safety glass, housings of cameras, reflectors for car headlights, mobile home glazing.

Thermal analysis of PC:

DSC:   Identification and characterization via glass transition; crvstallinity can only be detected in certain films.
TGA:   Degradation behavior, thermal stability, filler content.
TMA:  Glass transition, expansion behavior, expansivity, thermoplastic flow.
DMA:   Modulus, viscoelastic and damping behavior, glass transition.

10.Polyoxymethylene, POM

Polyoxymethylene, POM, or polyacetal is semicrystalline. Due to its high hardness and stiffness, POM is an excellent construction material for precision mechanics (screws, gear wheels, snap connections, mechanically stressed parts of office, household and textile machines).

Thermal analysis of POM:

DSC:   Characterization via melting behavior and crystallinity.
TGA:   Degradation behavior, filler content.
TMA:   Expansion behavior, expansivity.
DMA:   Modulus, viscoelastic and damping behavior, glass transition.

11. Polytetrafluoroethylene, PTFE

Polytetrafluoroethylene, PTFE, is a semicrystalline thermoplastic polymer with favorable wear resistance and low friction. In addition, the coefficients for static and sliding fricition are equal: no stick slip. Even more important are its excellent chemical, thermal and dielectric properties. PTFE has applications from very low temperatures up to approx. 250℃.

PTFE crystallites undergo an enantiotropic solid-solid transition at 19℃.
Applications of PTFE: seals, piston ring, pipes, bearings, anti-adhesive surface coatings.

Thermal analysis of PTFE:

DSC:   Identification and characterization via enantiotropic transition and melting behavior, crystallinity.
TGA:   Degradation behavior, filler content.
TMA:   Expansion behavior, expansivity, enantiotropic transition.
DMA:   Modulus, viscoelastic and damping behavior, glass transition.