Modification of Synthetic Isoprene Rubber with Phospholipid Concentrate during the Stage of Rubber Extraction from Polymerizate

In this study, synthetic ۱,۴-cis-polyisoprene rubber (SKI-۳) was modified with a phospholipid concentrate to bring its properties closer to those of natural rubber. The phospholipid concentrate (a mixture of phospholipids and vegetable oils) was introduced into the SKI-۳ polymerizate during the degassing stage (when the rubber is extracted from the isopentane polymerization solution) at a dosage of ۳–۷ parts per hundred parts of rubber (phr, by weight). The rubber was then extracted from the solution and dried at ۸۰ °C to constant weight. An identical sample of synthetic rubber without phospholipid was prepared as a control. Infrared spectroscopy confirmed the immobilization of phospholipid fragments onto the polyisoprene macromolecules, as evidenced by new absorption bands at ۱,۷۴۲ cm⁻¹ and ۳,۳۲۰ cm⁻¹ for carbonyl and hydroxyl groups, respectively, in the modified rubber. The effect of phospholipid content on the rubber’s properties was also examined. At an optimal loading of ۵ phr, the modified rubber exhibited higher cohesive strength. The Mooney viscosity of the rubber compounds increased at ۳ and ۵ phr loadings but decreased at ۷ phr. Thermogravimetric analysis (TGA) was used to assess thermal stability. The phospholipid-modified rubber showed enhanced thermal stability compared to the control. Overall, introducing phospholipids at the polymer extraction stage effectively enhanced the synthetic rubber’s physicomechanical properties and thermal stability, making its performance more comparable to that of natural rubber.

کلیدواژه ها:

synthetic polyisoprene ، Modification ، phospholipid concentrate ، rubber extraction