Semi-interpenetrating polymer networks based on liquid natural rubber

Abstract

<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:arial;mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">Semi-interpenetrating polymer networks based on liquid natural rubber polyurethane and linear polystyrene have been synthesized under different experimental conditions. The Semi-IPNs are found to be tough films and their physical, mechanical and thermal properties have been evaluated and compared with that of the homopolymer polyurethane and corresponding Full-IPNs. The density, shore-A Hardness and tensile strength of the Semi-IPNs indicated an increasing trend while percentage elongation at break decreases with increase in polystyrene content and also with increase in NCO/OH ratio. Crosslink density measurements indicated a possible phase inversion process for similar variations. These properties are found to be higher for Full-IPNs than Semi-IPNs except elongation at break, which is lower than Semi-IPNs. A marginal improvement in the thermal stability of Full-IPNs than the Semi-IPNs has been observe.</span>