ISSN:
0360-6376
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The bulk viscosity of polymethylhydrogensiloxane containing methoxy groups (PMHS-A) was measured before and after irradiation. The gel point was then determined from the variation of viscosity by irradiation by comparing it with methoxy-free polymethylhydrogensiloxane (PMHS-B) and polydimethylsiloxane blocked by methoxyldimethylsilyl (PDMS-C) or trimethylsilyl (PDMS-D). The following results were obtained: (1) The G value of crosslinking by irradiation is 167, 52, 25, and 3 for PMHS-A, PMHS-B, PDMS-C, and PDMS-D, respectively. (2) The scission of the SiO—CH3 bond is easier than that of the Si—H, Si—CH3, or SiCH2—H bond. The SiO—CH3 bond is PMHS-A is severed from SiO· and ·CH3 to induce chain reactions at the initial stage by irradiation. (3) It was confirmed that the commercial PMHS is at present free of methoxy groups. To replace the hydrogen of Si—H in the commercial PMHS with methoxy groups heat treatment with methanol was performed by which the G value of crosslinking was increased.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1979.170170624
