Abstract:

By using camphene, a derivative of turpentine, as a raw material; a flame-retardant monomer, N-trimethoxysilylpropyl-N-isobornylacrylamide (NPSBAM); and N-isopropylacrylamide (NIPAM), a flame-retardant copolymer—P(NIPAM-co-NPSBAM)—was prepared through the random copolymerization of NPSBAM and NIPAM. The structure, morphology, mechanical properties, and flame retardancy of the copolymer were analyzed. The results showed that the vibration peak of Si—O—C was found in the infrared spectrum, and the carbon-carbon double bond basically disappeared, which indicated that the turpentine silicone monomer NPSBAM was successfully introduced into the copolymer P(NIPAM-co-NPSBAM). Scanning electron microscopy revealed that the surface of NPSBAM-2 was rough, because of the introduction of the rigid ring.Moreover, as the content of NPSBAM increased, the water contact angle increased, indicating that the hydrophobicityof polyamide materialincreased. In addition, thermogravimetric analysis suggested that the introduction of the organosilicon monomer promoted carbon formation in the polyamide materials, and the amount of the residue increased with increasing organosilicon content. The analysis of the thermal decomposition kinetics indicated that with an increase in the content of the flame-retardant monomer, NPSBAM, the average activation energy increased from 123 to 166 kJ/mol. This indicated that the thermal stability of polyamide increased with an increase in the NPSBAM content. The mechanical property test showed that the tensile strength of polyamide increased from 5.2 to 7.2 MPa, which proved that the presence of the rigid ring in the turpentine monomer caused an improvement of the mechanical properties of polyamide. Furthermore, flame retardancy tests showed that the flame retardancy of the polyamide materials was improved.The limiting oxygen index(LOI)also increased from 16.4% to 23.9%.

Key words: turpentine, palyamide, retardant, organosilicon