Amorphous polyethylene terephthalate

Semicrystalline polyalkyl terephthalates are opaque due to diffraction of light as it crosses the interface between crystalline and amorphous regions. Amorphous polyethylene terephthalate has a low refractive index, making it appear glass-like in quenched parts. 

Fig. 1. Specific heat of amorphous polyethylene terephthalate as a function of temperature...

ABA ABS ABS-PC ABS-PVC ACM ACS AES AMMA AN APET APP ASA BR BS CA CAB CAP CN CP CPE CPET CPP CPVC CR CTA DAM DAP DMT ECTFE EEA EMA EMAA EMAC EMPP EnBA EP EPM ESI EVA(C) EVOH FEP HDI HDPE HIPS HMDI IPI LDPE LLDPE MBS Acrylonitrile-butadiene-acrylate Acrylonitrile-butadiene-styrene copolymer Acrylonitrile-butadiene-styrene-polycarbonate alloy Acrylonitrile-butadiene-styrene-poly(vinyl chloride) alloy Acrylic acid ester rubber Acrylonitrile-chlorinated pe-styrene Acrylonitrile-ethylene-propylene-styrene Acrylonitrile-methyl methacrylate Acrylonitrile Amorphous polyethylene terephthalate Atactic polypropylene Acrylic-styrene-acrylonitrile Butadiene rubber Butadiene styrene rubber Cellulose acetate Cellulose acetate-butyrate Cellulose acetate-propionate Cellulose nitrate Cellulose propionate Chlorinated polyethylene Crystalline polyethylene terephthalate Cast polypropylene Chlorinated polyvinyl chloride Chloroprene rubber Cellulose triacetate Diallyl maleate Diallyl phthalate Terephthalic acid, dimethyl ester Ethylene-chlorotrifluoroethylene copolymer Ethylene-ethyl acrylate Ethylene-methyl acrylate Ethylene methacrylic acid Ethylene-methyl acrylate copolymer Elastomer modified polypropylene Ethylene normal butyl acrylate Epoxy resin, also ethylene-propylene Ethylene-propylene rubber Ethylene-styrene copolymers Polyethylene-vinyl acetate Polyethylene-vinyl alcohol copolymers Fluorinated ethylene-propylene copolymers Hexamethylene diisocyanate High-density polyethylene High-impact polystyrene Diisocyanato dicyclohexylmethane Isophorone diisocyanate Low-density polyethylene Linear low-density polyethylene Methacrylate-butadiene-styrene... 

Amorphous polyethylene terephthalate) is not suited to welding by these means the material may be modified with glycol to make formings for packaging, and this modified material can be tear-sealed. 

In Fig. 11.1 the time dependent dielectric constant (left) and both dynamic dielectric constants (right) are plotted vs. reduced time, t/x, and reduced angular frequency, cox, respectively, for amorphous polyethylene terephthalate at 81° C. It illustrates a continuous increase of s(t) from 3.8 to 6. It also shows that the e (co) decreases with frequency in a similar way as e(t) increases with time. The maximum in s", situated at cox = 1, is equal to (fis— oo)/2 = 1.1. A Cole-Cole plot where s" is plotted vs. s is shown in Fig. 11.2. For a Debye model with only one relaxation time this should be a semi-circle. In reality the decrease of s from s to 00 is not so fast and the maximum in s" not so sharp as the Debye... 

Komolprasert V, McNeal TP, Begley TH. Effects of gamma- and electron beam irradiation on semi-rigid amorphous polyethylene terephthalate copolymers. hood Addit Contain 2003 20(5) 505 17. 

Sasabe and Saito [102] reported that the following empirical equation [Eq. (14)] was observed between x and G for some amorphous polymers poly(vinyl chloride), poly(vinylidene chloride), poly(vinyl acetate), amorphous polyethylene terephthalate), and polycarbonate. 

Many crystallizable polymers can be prepared in the amorphous glassy state by rapid quenching as films. Measurements of Aglass transition temperature determined. Such results are shown for amorphous polyethylene terephthalate (PET) in Figure 13 (17). The Brillouin splittings change slope at 70°C. If both Aa>(i) and Awt can be measured, the Poisson ratio (T can be determined according to ... 

AI artificial intelligence APET amorphous polyethylene terephthalate... 

P.R. Pinnock and I.M. Ward, Stress-optical properties of amorphous polyethylene terephthalate fibres. Trans. Faraday Soc. (1966), p. 1308. 

Figure 13.6 Resolution of multiple transitions in amorphous polyethylene terephthalate by dielectric thermal analysis, (a) e curves defining polyethylene terephthalate transitions (b) e" curves showing frequency dependency of alpha beta transitions.

Figure 6.6 Tensile modulus and loss factor tand for unoriented amorphous polyethylene terephthalate (a) and unoriented crystalline polyethylene terephthalate (b) as a function of temperature at 1.2 Hz (x) modulus ( ) land. (Reproduced with permission from Thompson and Woods, Trans. Faraday Soc., 52, 1383 (1956))...

Other workers have carried out comparisons of Tg determined by DMTA and DSC. Good agreement as obtained for amorphous polyethylene terephthalate (PET) -polyethylene naphthalate bonds [9], aromatic polyimides [10], epoxy-based divinyl ester resin-styrene copolymers [11], bisphenol A-epoxy diacrylate-N-vinyl pyrrolidine networks [12], and polyesters [13]. 

Figure 12.29 Ratio of shear yield stress to shear modulus as a function of temperature at different strain rates, for amorphous polyethylene terephthalate. Points from unpublished data of Foot and Ward, curves from Argon theory. Strain rates X, 1.02 x CPs +, 21.4 s - V,...

Amorphous polyethylene terephthalate is a glassy polymer. During exposure to temperatures below glass transition temperature, molecular rearrangements facilitate equilibrium in the material. This process changes the free volume and causes a reduction in relaxation enthalpy. 

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