DETECTION OF A NEW CROSS-LINKING AND PROPERTIES OF LIQUID POLYSULFIDEPOLYMER

Polysulfide polymer was found in the 19th century. At present, this po lymer consists of the repetition of disulfide linkage and diethyl form al and has SH terminals. This liquid polymer (LP) is cured by lead dio xide. We studied polysulfide polymerization and elastomeric mechanical properties of cured LP. The condition of polymerization greatly influ enced its elastomeric mechanical properties. These phenomena could not be explained from the point of residual unreacted chlorine or produce d OH terminals. We found that additional crosslinking sites are produc ed during polymerization besides crosslinking agents trichloropropane (TCP) by using the Insensitive Nuclei Enhanced by Polarization Transfe r (INEPT) method. We proposed their chemical structures and reaction s cheme of their formation. TCP and also these additional crosslinking s ites influence the modulus of cured LP. The sum of the intensity of th eir crosslinking sites by C-13-NMR had good correlation with 300% modu lus of cured LP. (C) 1999 John Wiley & Sons, Inc.