Synthesis and properties of low-crystallinity nylon 6 with high transparency and low hygroscopicity containing adipic acid

In this research, a series of amorphous nylons 6 were prepared by introducing adipic acid and different structure amines into the copolymerization with caprolactam. The effects including thermal properties, crystallinity, dynamic mechanical properties, optical properties, and water absorption of different copolymerization structure and copolymerization ratio on the properties of nylon 6 were investigated. The results show the melting point and thermal cracking temperature Td 5 of nylon 6 are, respectively, between 179[Formula: see text]C and 217[Formula: see text]C and 278[Formula: see text]C to 336[Formula: see text]C. Nylon 6 structure introducing a methyl side chain is more effective than a meta-benzene ring, a meta-cycloalkyl, and bicycloalkyl groups, so CAMM and CAI have the lowest crystallinity.

Synthesis and Physical Properties of Non-Crystalline Nylon 6 Containing Dimer Acid

In this study, a long carbon chain dimer acid is introduced into a nylon 6 structure and is copolymerized with different structural amines to produce amorphous nylon 6 by 4,4′-methylenebis(2-methylcyclohexylamine) (MMCA) in different copolymerization ratios. The effect of different structures and copolymerization ratios on the properties of nylon 6 is determined, along with the thermal properties, crystallinity, water absorption, dynamic mechanical properties, and optical properties. It is found that the melting point and the thermal cracking temperature Td10 of nylon 6 are respectively between 176 °C and 213 °C and 378 °C to 405 °C. The effect of introducing a bicyclohexane group containing a methyl side chain is greater than that of a meta-benzene ring, so COMM (synthesized by Caprolactam (C), dimer oleic acid (OA), and 4,4′-Methylenebis(2-methylcyclohexylamine) (MMCA)) has the lowest melting point, enthalpy, and crystallinity. As the copolymerization ratio increases, its thermal properties decrease. 10% is the lowest crystallinity. The amine structure containing a bicycloalkyl group has lower water absorption and a 10% copolymerization ratio gives the lowest water absorption. It contains the bicycloalkyl group, COM (synthesized by Caprolactam (C), dimer oleic acid (OA) and 4,4′-Methylenebis(cyclohexylamine) (MCA)), which has the highest loss modulus. The lowest loss modulus is noted for a copolymerization ratio of 7% and the value of tan δ increases as the copolymerization ratio increases. The introduction of nylon 6 with the bicycloalkyl groups, COMM and COM, significantly increases transparency. As the copolymerization ratio increases, the transparency increases and the haze decreases. The best optical properties are achieved for 10% copolymerization.

Study on an Aliphatic Polyurethane Laminating Adhesive Based on Castor Oil

The first component of the Polyurethane adhesive was prepared with polyester polyol, polyether polyol ,castor oil and isophorone diisocyanate. And this component was mixed with the castor oil and its modified production to prepare a two-component solvent-free aliphatic polyurethane laminating adhesive. In this study, the influences of the copolymerization ratio of polyester/ether on viscosity, heat resistance, adhesion strength and boiling resistance were studied, as well as influences of castor oil and its modified production on curing speed and adhesion strength. The results showed that when proportion of polyether diol was 25% and castor oil was 50% of the total hydroxyl content of first component, the PU adhesive with lower viscosity, better reactivity and enhanced boiling resistance would be achieved. And with an appropriate amount of derivatives castor oil in second component, the curing speed and adhesion strength of the PU adhesive were significantly improved.