Resistance function, polycarbonate

The polycarbonate glazing is modeled as a simply supported plate subjected to nonlinear center deflections up to 15 times the pane thickness. Using the finite element solution of Moore (Reference 4), the resistance function is generated for each pane under consideration. Typically, the resistance is concave up, as illustrated for typical pane sizes in Figure 1. This occurs because membrane stresses induced by the stretching of the neutral axis of the pane become more pronounced as the ratio of the center pane deflection to the pane... 

In many cases, the dynamic amplification factor or the ratio of static load to dynamic load capacity will exceed two. This is because of the concave up shape of the resistance function and the mobilization of membrane resistance at large deflection to thickness ratios. Because of this phenomenon, it is unconservative to assume the blast capacity of polycarbonate glazing to be no less than one half of its static pressure load capacity. 

Polycarbonate has good mechanical strength, is heat resistant, has dimensional stability, and is widely used as a general purpose engineering plastic. However, its viscosity, chemical resistance, and dependence of impact strength on wall thickness are not suitable for some applications. Idemitsu alloys are highly-functional polycarbonate-based polymer alloys. While retaining the best properties of polycarbonate the as above mentioned problems have been virtually eliminated. 

Up to a temperature of 60 °C, the resistance of polycarbonate to water can be considered good. Only higher temperatures and constant contact with water will cause gradual saponification with molecular mass degradation as a function of time and temperature. Polycarbonate behaves more favorably under repeated, but only shortterm contact with hot water. Lightly stressed polycarbonate dishes can, e.g., be washed in dishwashers more than 1000 times without unfavorable changes. Parts molded from polycarbonate can also be repeatedly steam sterilized. 

Amorphous polyamides, preferably copolyamides from iso- and terephthalic acid with hexamethylene diamine have gained importance as components in polymer blends with polycarbonate, polyphenylene ether and/or functionalized elastomers, and also with the semi-crystalline polyamides 6 and 66. These copolyamides increase the chemical resistance of polycarbonate or polyphenylene ether and reduce stress-cracking sensitivity to concentrated zinc chloride solution in polyamide 6 and 66. Moreover, these copolyamides provide for improved compatibility. 

The abihty of organically modified ceramics based on alumina, zkconia, titania, or siUca (and mixtures of each) to function as abrasion-resistant coatings has also been studied (62). Eor example, polycarbonate, when coated with an epoxy—aluminosihcate system, experiences a significant reduction in the degree of hazing induced by an abrader, as compared to uncoated polycarbonate. 

The specialty class of polyols includes poly(butadiene) and polycarbonate polyols. The poly(butadiene) polyols most commonly used in urethane adhesives have functionalities from 1.8 to 2.3 and contain the three isomers (x, y and z) shown in Table 2. Newer variants of poly(butadiene) polyols include a 90% 1,2 product, as well as hydrogenated versions, which produce a saturated hydrocarbon chain [28]. Poly(butadiene) polyols have an all-hydrocarbon backbone, producing a relatively low surface energy material, outstanding moisture resistance, and low vapor transmission values. Aromatic polycarbonate polyols are solids at room temperature. Aliphatic polycarbonate polyols are viscous liquids and are used to obtain adhesion to polar substrates, yet these polyols have better hydrolysis properties than do most polyesters. 

Whereas the tensile strength was not a sensitive function of the monomer structure, the tensile modulus (Young s Modulus) was clearly related to the monomer structure. This is expected since the tensile modulus is a measure of the polymer s resistance to deformation and is related to the "stiffness" of a polymeric material. The highest tensile modulus (22,000 kg/cm2,2.2 GPa) was measured for poly(BPA iminocarbonate). Replacement of BPA by Dat-Tyr-Hex reduced the tensile modulus significantly. This observation can possibly be attributed to the presence of the long hexyl ester pendent chain in Dat-Tyr-Hex. Generally, the polyiminocarbonates were somewhat "stiffer" than the corresponding polycarbonates. Thus, the tensile moduli of poly(Dat-Tyr-Hex iminocarbonate) and poly(Dat-Tyr-Hex carbonate) were 16,300 kg/cm2 (1.6 GPa) and 13,900 kg/cm2 (1.3 GPa) respectively. 

Boronic acids (69 and 70) (Fig. 45) with more than one boronic acid functionality are known to form a polymer system on thermolysis through the elimination of water.93 Specifically, they form a boroxine (a boron ring system) glass that could lead to high char formation on burning. Tour and co-workers have reported the synthesis of several aromatic boronic acids and the preparation of their blends with acrylonitrile-butadiene-styrene (ABS) and polycarbonate (PC) resins. When the materials were tested for bum resistance using the UL-94 flame test, the bum times for the ABS samples were found to exceed 5 minutes, thereby showing unusual resistance to consumption by fire.94... 

Medium-ilow, general purpose grade. fHeat-resistant grade. Impact values for polycarbonates are a function of thickness. 11000-psi load, ft At 1% deformation. From Rexall-Fiberfil data. 

Gao B, Feng Y, Lu J, Zhang L, Zhao M, Shi C, et al. Grafting of phosphorylcholine functional groups on polycarbonate nrethane surface for resisting platelet adhesion. Mater Sci Eng C Mater Biol Appl 2013 33(5) 2871-8. 

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