Copolyamide, isophthalic acid

Random copolyamides are also obtained from MDI or TDI with mixtures of isophthalic acid and 4,4 -oxydibenzoic acid. ° Multiblock copolymers are also obtained by reacting a mixture of isophthalic acid and azelaic acid with MDI to form a prepolymer, which is subsequently reacted with a, ty-bis(10-carboxy-decyl)polydimethylsiloxane. ... 

In fact, the photochemical process is much less sensitive to the rigidity of the system if the azobenzene is attached as a side chain. Copolymer ABA-MMA exhibited a quantum efficiency only 4-5 times lower in a glassy film then in dilute solution (8). By contrast, Figure 3 shows the relative quantum efficiencies for the trans-cis isomerization of a copolyamide of isophthalic acid with 4,4 -diaminodiphenyl sulfone containing a small proportion of... 

Figure 3. Photoisomerization of isophthalic acid copolyamide with 4,4 -diamino-diphenylsulfone and 494f-diaminoazobenzene...

Materials. High density polyethylene (HDPE) having different molecular weights, and specific gravity of 0.951 (Marlex 5202, HXM 50100, made by Phillips 66 Co), were used for extrusion applications. Polyamides used were a semicrystalline copolyamide of adipic acid, hexamethylene diamine and caprolactam, and a copolyamide containing isophthalic acid as well. An anhydride modified polyethylene (3-5) as an interlaminar adhesive/compatibilizer was also used. The combinations are generally included in "Selar" barrier materials supplied by E. I. du Pont de Nemours Co. 

PA12/MACMI Copolyamide based on omega-aminododecanoic acid (laurolactame) and 3,3 -dimethyl-4,4 -diaminodicyclohexylmethane and isophthalic acid... 

PA6T/6I Copolyamide based on hexamethylenediamine, terephthalic and isophthalic acid... 

Homopolymers derived from MDI and azelaic acid are semicrystalline engineering plastics with a Tg of 135°C and a Tm of 290°C (88). Copoljrmers of MDI with azelaic acid, containing 20-30 mol% of adipic acid show a eutectic Tm of approximately 240°C. These amorphous or slightly crystalline copolymers have mechanical properties comparable to transparent nylons or polycarbonates. Although injection molded samples are transparent, they will crystallize and turn opaque. Copolyamides derived from MDI and aromatic dicarboxylic acids are more difficult to prepare. Because of the very high Tm (420°C) of the isophthalic acid/MDI block it was necessary to prevent the formation of any appreciable ciystalline blocks, which was accomplished by prereacting a portion of the isophthalic acid (15-20 mol%) with 2,4-TDI. In this manner crystallization of the isophthalic acid/MDI blocks was surpressed (89). Thus, copolyamides containing IPA/azelaic acid (50 50) are obtained with thermal and mechanical properties similar to poly-sulfone. 

By using mixtures of adipic and azelaic acids as monomers in the reaction with MDI, transparent copolymers are obtained useful as engineering thermoplastics. Also, copolyamides obtained from mixtures of isophthalic (IPA) and azelaic acids and MDI/TDI mixtures have been made. TDI in combination with MDI is used to lower the melt temperature of the IPA/MDI blocks to allow thermoplastic processing. 

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