Blends linear polyesters

Materials are also blended with VDC copolymers to improve toughness (211—214). VinyHdene chloride copolymer blended with ethylene—vinyl acetate copolymers improves toughness and lowers heat-seal temperatures (215,216). Adhesion of a VDC copolymer coating to polyester can be achieved by blending the copolymer with a linear polyester resin (217). 

Highly compatible polymer blends of PPE and linear polyester resins provide beneficial improvements in the chemical resistance required for automotive applications. Such automotive applications include molded thermoplastic body panels. Foamable compositions of PPE resins are particularly suited as sources of lightweight structural substitutes for metals, especially in the automotive industry. 

J. B. Yates, HI and G. F. Lee, Jr. Compatible polyphenylene ether-linear polyester blends having improved impact sfiength. US Patent 5 008 333, assigned to General Electric Co. (Selkirk, NY), April 16, 1991. 

These systems, whose phase characteristics resemble those of the polyblends discussed in Chapter 3, can be prepared by first blending the molten polymers together until the minor component is dispersed in the form of droplets that are small in comparison to the fiber diameter desired (Allied Chemical Corp., n.d. Buckley and Phillips, 1969 Hayes, 1969 Mumford and Nevin, 1967 Papero et a/.,1967). The material is then melt-spun and drawn in order to orient both constituents and cause the dispersed phase to form elongated cylinders or fibrils. For satisfactory dispersion, the viscosities of both components must be comparable (for a discussion of rheological effects in molten polymer blends, see Section 9.6). An important biconstituent system is based on a combination of nylon 6 with a linear polyester poly(ethylene terephthalate), with nylon 6 as the continuous phase (Buckley and Phillips, 1969). As shown in Figure 9.5, fibrils of polyester... 

Following up on the work that used knitted brics as extension sensors to measure breathing rate 000, some samples were knitted in three different structures, using a yam that is a blend of polyester and stainless steel in a proportion of 80/20 % (Bekaert Bekinox Nm 50) and has a perfectly textile touch comparing to a pure stainless steel yam. lire first experiments showed that the sensors had limited performance. The main problems presented by this sensor are its high non-linearity and hysteresis, and an evident instability of the electrical resistance values measured, producing a fluctuation of the signals. 

Poly(3-hydroxybutyrate) (PHB) 8 was a commercially available, biodegradable, non-linear polyester. Kumagai and Doi established that this polymer (M = 652,000, M /M =l.8) is immiscible with PCL (M =68,000, M /M =1.9) when solvent cast from chloroform [113]. Samples studied by DSC showed two glass-transition temperatures, identical with those of the individual components and invariant with composition. Mechanical properties of the blends were poor and tensile modulus and strength were minimal at 50 wt % of the components. PCL had a complex and accelerating influence on the rate of enzymatic degradation of PHB, the kinetics of which were correlated with scanning electron microscopy observations. 

Blends of primary anti-oxidants and a high-temperature hydrolytically stable organophosphite secondary anti-oxidant have been developed for high-temperature processing of polyolefins, polyamides, and polycarbonates in colour-critical applications. Irganox LM blends of primary anti-oxidants and a new phosphite processing stabilizer offer melting at 90°C and can be applied to polymer reactor products, especially polyolefins, linear polyesters, polycarbonates, polyamides, HIPS, ABS, SAN, and elastomers. 

BASF has introduced their aliphatic-aromatic copolyesters (AAC) product under the name Ecoflex . This material is widely used to produce compostable packaging and films. According to the BASF s corporate website, annual production of Ecoflex has risen to 60,000 MT to keep up with the demand for biodegradable plastics, which is growing at a rate of 20% per year. At the same time, BASF also produces a blend of polyester and PLA — a product called Ecovio . This high-melt-strength polyester—PLA can be directly processed on conventionally blown film lines without the incorporation of additives. Moreover, Ecovio has extraordinary puncture-and tear-resistance and weldability. Another company, Eastman, has also produced AAC, with the tradename Eastar Bio . Eastar Bio has a highly linear structure, while Ecoflex contains... 

Polybutyleneterephthalate (PBT) is of growing interest as a material for injection molding. In fact, its rate of crystallization is faster than that of the other widely used linear polyesters such as polyethyleneterephtha-late (PET). However, PBT shows a low impact resistance, particularly at low temperatures. For this reason the uses of PBT are limited. The usual method to overcome this limitation is to add a second elastomeric phase to the PBT matrix. Rubber modification of PBT has been realized by melt blending with preformed rubbers such as poly(ethylene-co-vinylacetate) (EVA) and poly(ethylene co-vinylalcohol) (EVOH) [71], or by adding end-capped polymers to produce a second flexible component during PBT polymerization. 

Staple. PET staple is widely used in 100% polyester or cotton-blend fabrics for apparel. Typical cotton-blend polyester staple fibers have a linear... 

Along with cotton blends, polyester blends with rayon or wool are also important. Wool—polyester blends are widely used in men s suiting materials. For these fabrics, PET staple or tow can be used with a linear density typically about 0.16—0.45 tex per filament (1.5—4 dpf) and a staple length of 50—75 mm (2—3 in.). 

Typical textile fibers used, for example, in a needle-punched filter fabric, are a blend of 3.3- and 6.6-dtex (3- and 6-denier) polyester staple. These fibers are - 5 cm long, have diameters ranging from 18 to 25 pm, mass-per-unit-length or linear density values ranging from - 350 to 650 mg per 1000 m, and length-to-width ratios in the order of 1000 to 1. 

FIG. 24 Effect of partial replacement of linear alkylbenzesulfonate by a-olefinsulfonate (AOS) in surfactant component of carbonate-built product formulation on detergency of polyester-cotton (50 50 blend). (From Ref. 3.)... 

Massa, Voit, and coworkers1231 conducted a survey of the phase behavior of blends of these polyester hyperbranched polymers with linear polymers. Blend miscibility of a hydroxyl terminated polyester was comparable to that of poly(vinylphenol) indicating strong H-bonding interactions, whereas miscibility of an acetoxy terminated analog decreased relative to the hydroxy derivative. 

A wide range of thermoplastic starch compounds have been claimed in recent years. Formulations of thermoplastic starch with linear, biodegradable polyesters, including polycaprolactone and PHBV,174 176 and with polyamides175 have been reported. Laminated structures have been claimed using thermoplastic starch or starch blends as one or more of the layers.175,177,178 The use of polymers latexes as components of thermoplastic starch blends has also been claimed.179 181 Blends with natural polymers are also claimed, including cellulose esters182,183 and pectin.184 A crosslinked thermoplastic material of dialdehyde starch and protein has been reported.185... 

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