Tensile modulus copolymers

The copolymer fiber shows a high degree of drawabiUty. The spun fibers of the copolymer were highly drawn over a wide range of conditions to produce fibers with tensile properties comparable to PPT fibers spun from Hquid crystalline dopes. There is a strong correlation between draw ratio and tenacity. Typical tenacity and tensile modulus values of 2.2 N/tex (25 gf/den) and 50 N/tex (570 gf/den), respectively, have been reported for Technora fiber (8). 

Branchings Uniformity. Comparison of uniformly and nonuniformly branched ethylene—1-butene copolymers of the same density (Table 4) shows that uniformly branched resins are much more elastic, their tensile modulus is lower, and their strain recovery is neady complete. 

Commerical grades of EVOH typically have vinyl alcohol contents in the range 56-71%, but in contrast to the corresponding EVA materials these copolymers are crystalline. Furthermore, an increase in the vinyl alcohol content results in an increase in such properties as crystalline melting point, tensile strength and tensile modulus together with a decrease in oxygen permeability. This is a reflection of the fact that the ethylene and vinyl alcohol units in the chain are essentially isomorphous (see Sections 4.4 and 14.3.1). 

Copolymer Tensile modulus (MPa) Tensile strength (MPa) Elongation (%) Izod impact strength (J/m) Compression set/% (70 °C, 22 h)... 

The effect of the microstructure of acrylic copolymer/terpolymer on the properties of silica-based nanocomposites prepared by the sol-gel technique using TEOS has been further studied by Patel et al. [144]. The composites demonstrate superior tensile strength and tensile modulus with increasing proportion of TEOS up to a certain level. At a particular TEOS concentration, the tensile properties improve with increasing hydrophilicity of the polymer matrix and acrylic acid modification. 

Blends of syndiotactic styrene-/ -methylstyrene copolymers (SPMS) with poly(styrene)-block-poly(ethylene-co-butylene)-block-polystyrene (SEBS) has been reported. [21] No significant effects on the tensile modulus and strength were observed for blends containing less than 10% SEBS. SEM of drawn samples of the blends showed that the dispersed SEBS phase had been extended to about the same extent as the bulk blend, indicating good adhesion between the two phases. 

A copolymer containing an 80 20 molar ratio of norbornene and 5-triefhoxysilylnorbornene made using the (/7 -toluene)Ni(C6F5)2 initiator (Section 4.2.3.9) had a tensile modulus of 1.4 GPa, an elongation to break of 15% and a Tg of 355 °C. This material exhibited excellent transparency wifh greater fhan 90% average transmission between 400 and 700 nm and a low dielectric constant (2.67) suggesting fhat this material could find utility in optical and electronic applications [78]. 

Finally, the ethylene/norbornene copolymers obtained using the nickel catalysts are essentially indistinguishable from those obtained using metaUocene-based early transition metal catalysts, both in terms of the microstructure and such physical properties as Tg and tensile modulus. For the ethylene/norbornene polymers synthesized, the glass transition temperature (Tg) increases smoothly with increasing norbornene content. 

PSF with crosslinked acrylate copolymer, crosslinked SAN, and uncrosslinked SAN good tensile modulus, yield strength, impact resistance, and respectable HDT = 106°C Robeson, 1985... 

Polyamides and polyesteramides are more recent arrivals to the commercial biodegradable polymer field. Copolymers of either glycine or serine with e-aminocaproic acid are biodegradable. For example, biodegradable polyaspartic acid was synthesized (95% yield) at low cost [Koskan, 1992]. A copolymer of butylene-adipate and e-caprolactam was recently introduced by Bayer as BAK 1095. The material has T = 125°C, density of 1070 kg/m, tensile modulus of 180 MPa, maximum strain at break of 400%, tensile stress at break of 25 MPa, and it fully degrades in 300 days under the ASTM standard conditions. 

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