Miscibility between natural rubber and tackifiers. II. Phase diagrams of the blends of natural rubber and petroleum resins

✍ Scribed by Michiko Fujita; Mikio Kajiyama; Akio Takemura; Hirokuni Ono; Hiroshi Mizumachi; Shunji Hayashi

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 267 KB
• Volume: 67
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19980110)67:2<221::aid-app4>3.0.co;2-w

✦ Synopsis

Natural rubber (NR) was blended in various ratios with 12 kinds of tackifiers that were prepared from petroleum. The blends were heated to various temperatures (20-120ЊC) to investigate their miscibility. The blends were visually observed for transparency or opacity at each temperature and further observed under an optical microscope for any existence of phase-separated structure. Miscibility of the blends is illustrated as phase diagrams in this article. NR/aliphatic resin systems and NR/ aliphatic-aromatic copolymer systems showed phase diagrams of the lower critical solution temperature type, wherein the blends turned faintly cloudy over the binodal curves. The NR/hydrogenated petroleum resin system also showed a phase diagram of the lower critical solution temperature type. The miscible range of a blend system tends to become smaller as the molecular weight of a tackifier increases. Resins prepared by polymerization of pure aromatic monomers were completely immiscible with NR.