Polycarbonate mechanical properties

Blends with good mechanical properties can be made from DMPPO and polymers with which DMPPO is incompatible if an appropriate additive, compatibilizing agent, or treatment is used to increase the dispersion of the two phases. Such blends include mixtures of DMPPO with nylon, polycarbonate, polyester, ABS, and poly(phenylene sulfide). 

Table 20.3 Comparison of mechanical properties of typical commercial bis-phenol A polycarbonates...

Typical mechanical properties for bis-phenol A polycarbonates are listed in Table 20.3. 

ABS has a specific gravity of 1.03 to 1.06 and a tensile strength in the range of 6 to 7.5 X 10 psi. These polymers are tough plastics with outstanding mechanical properties. A wide variety of ABS modifications are available with heat resistance comparable to or better than polysulfones and polycarbonates (noted later in this section). Another outstanding property of ABS is its ability to be alloyed with other thermoplastics for improved properties. For example, ABS is alloyed with rigid PVC for a product with better flame resistance. 

Polycarbonate Good/Excellent Yellows. Mechanical properties not greatly... 

Polycarbonate (PC) serves as a convenient example for both, the direct determination of the distribution of correlation times and the close connection of localized motions and mechanical properties. This material shows a pronounced P-relaxation in the glassy state, but the nature of the corresponding motional mechanism was not clear 76 80> before the advent of advanced NMR techniques. Meanwhile it has been shown both from 2H NMR 17) and later from 13C NMRSI) that only the phenyl groups exhibit major mobility, consisting in 180° flips augmented by substantial small angle fluctuations about the same axis, reaching an rms amplitude of 35° at 380 K, for details see Ref. 17). 

Other reports on the morphology and mechanical behavior of organosiloxane containing copolymeric systems include polyurethanes 201 202), aliphatic 185, 86) and aromatic117,195> polyesters, polycarbonates 233 236>, polyhydroxyethers69,311, siloxane zwitterionomers 294 295) and epoxy networks 115>. All of these systems display two phase morphologies and composition dependent mechanical properties, as expected. 

Polycarbonates are used in optics, transparent technical parts, aesthetic applications and protection devices for their transparency, mechanical properties, impact resistance, rigidity, good creep behaviour, fatigue resistance, insulating properties, dimensional stability, low moisture uptake, broad range of service temperatures (-100°C up to -i-135°C),food contact and sterilization possibilities for suitable grades. 

The polycarbonate membranes are stretch-oriented during fabrication in order to improve their mechanical properties. If the membrane is subsequently heated above its glass-transition temperature ( 150°C), the polymer chains relax to their unstretched conformation and the membrane shrinks. This shrinking of the membrane around the Au nanowires in the pores causes the junction between the nanowire and the pore wall to be sealed. This is illustrated in Fig. 5, which shows voltammograms for tri-methylaminomethylferrocene (TMAFc+) before (Fig. 5A) and after (Fig. 

In general, substitution of polar atoms and polar groups for nonpolar or less polar moieties results in an increase in the Tg and such mechanical properties as yield stress and modulus. Thus condensation polymers such as nylons, polycarbonate (PC), and polyesters are typically higher-melting and exhibit higher Tg s, tensile strength and associated properties, but typically lower impact strengths and associated properties which require some flexibility (Table 5.3). 

S.C. Tjong and Y.Z. Meng, Effect of reactive compatibilizers on the mechanical properties of polycarbonate/poly(acrylonitrile-buta-diene-styrene) blends, Enr. Polym. J., 36(1) 123-129, January 2000. 

In the early literature it is suggested that polycarbonates can be easily plasticized with common plasticizers. Plasticization of polycarbonate has been investigated by Kozlov et al. (12). These authors described the influence of plasticization on softening points and mechanical properties of bisphenol A polycarbonates. They conclude that the behavior of plasticized polycarbonate is similar to that encountered for most amorphous polymers. The influence of crystallization effects promoted by the plasticizer was not taken into account. 

The mechanical properties and the tensile heat distortion temperatures (softening temperatures) of cast and pressed polycarbonate films containing differing amounts of plasticizer have been measured (Table III and IV). 

Mechanical Properties. The room temperature modulus and tensile strength are similar to those of other amorphous thermoplastics, but the impact strength and ductility are unusually high. Whereas most amorphous polymers arc glass-like and brittle below their glass-transition temperatures, polycarbonate remains ductile to about — 10°C. The stress-strain curve for polycarbonate typical of ductile materials, places it in an ideal position for use as a metal replacement. Weight savings as a metal replacement are substantial, because polycarbonate is only 44% as dense as aluminum and one-sixth as dense as steel. 

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