Polyamide thermal property data

Table 8. Basic thermal properties data of polyamides Reprinted from [a.341] with permission from Elsevier ...

Fig. 6-14 specific modulus = modulus/density. Plastics include use of the heat-resistant TPs such as the polimides, polyamide-imide, and others. Table 6-21 provides data on the thermal properties of RPs. To date at least 80 wt % are glass fiber and about 60 wt% of those are polyester (TS) type RPs. 

Thermal stability as measured by these ramped TGA experiments of the sort previously described are not the definitive test of a polymer s utility at elevated temperature. Rather, for a polymer to be useful at elevated temperatures, it must exhibit some significant retention of useful mechanical properties over a predetermined lifetime at the maximum temperature that will be encountered in its final end use application. While many of the bisbenzocyclobutene polymers have been reported in the literature, only a few have been studied in detail with regards to their thermal and mechanical performance at both room and elevated temperatures. Tables 7-10 show some of the preliminary mechanical data as well as some other physical properties of molded samples of polymers derived from amide monomer 32, ester monomer 40, diketone monomer 14 and polysiloxane monomer 13. The use of the term polyamide, ester etc. with these materials is not meant to imply that they are to be regarded as merely modified linear thermoplastics. Rather, these polymers are for the most part highly crosslinked thermosets. 

Effect of Chain Length. The initial part of this study consisted of determining the effect of aliphatic chain length on the permeation properties of the polyamides. A series of isophthal-amides (n-I) was prepared where the aliphatic chain length was systematically altered from 2 to 10 methylenes (5). Crystalline melting points were observed by DSC for 2-1 and 1-1, so permeation data was measured only for 4-1 through 10-1. The thermal, density, and oxygen permeation data for this series are contained in Table I. 

Koo and co-workers [78] attempted to develop polyamides 11 and 12 with enhanced flame retardancy and thermal and mechanical properties by the incorporation of montmorillonite clays, silica and carbon fibre-polymer nanocomposites. Flammability properties of the nanocomposites were compared with those of the virgin polyamides, using cone calorimetry with an external heat flux of 50 kW/m. Cone calorimetry was also used in an evaluation of polyamide 6 - anion modified Mg/Al interlayer formulation [79]. The data from the cone calorimeter shows that the heat production rate (HPR) and mass loss weight of the sample with 5 wt% MgAl(H-DS) decrease considerably to 664 kW/mVs and 0.161 g/mVs from 1064 kW/mVs and 0.252 g/mVs... 

Table 3 contains reaction conditions and polymer properties for polybenzoxazoles prepared by one-step thermal polymerizations and by cyclization of the intermediate polyamides. The latter dehydration process was readily followed by IR. The polyamides have strong bands near 1655 cm which gradually disappear during the cyclization. Concomitant appearance of the characteristic benzoxazole band at 1600-1620 cm confirms the process and the product structure. In addition, microanalysis data have been obtained for the polybenzoxazoles from monomers and Calculated and found values for C, H, and N were within 0.3% of each other for the former. The values for the latter were consistent with either equivalent of bound H2O per repeat unit and/or incomplete cyclization. 

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