|
" Syntheses and characterization of siloxane-containing polymers and IPNs "
X. Lin
I. Cabasso
| Document Type
|
:
|
Latin Dissertation
|
| Language of Document
|
:
|
English
|
| Record Number
|
:
|
1113215
|
| Doc. No
|
:
|
TLpq304266067
|
| Main Entry
|
:
|
I. Cabasso
|
|
|
:
|
X. Lin
|
| Title & Author
|
:
|
Syntheses and characterization of siloxane-containing polymers and IPNs\ X. LinI. Cabasso
|
| College
|
:
|
State University of New York College of Environmental Science and Forestry
|
| Date
|
:
|
1996
|
| student score
|
:
|
1996
|
| Degree
|
:
|
Ph.D.
|
| Page No
|
:
|
245
|
| Abstract
|
:
|
Siloxane-containing polymers and interpenetrating polymer networks (IPNs) were synthesized and characterized. Sulfonated polyethylene (SPE) served as a polymer-bound catalyst for the polymerization of cyclosiloxane monomers. This catalyst was prepared by chlorosulfonation of polyethylene with SO2/Cl2 in chlorinated solvent. The synthesis of SPE in flat sheet and hollow fiber configurations is reported herein. Cationic ring-opening bulk polymerization of octamethylcyclotetrasiloxane (D4), which was catalyzed by the SO3H groups of SPE, is described. This study was split into two parts: polymerization of the cyclosiloxane monomer in the bulk solution, and polymerization in the matrix of the SPE. In the former, only the surface of the SPE induced the polymerization. A complex equilibrium polymerization composed of competing reactions involving both cyclic and linear species was observed. Formation of an ultrathin growing layer of PDMS on the SPE surface was observed and studied. In the second part, the monomers that diffused into the SPE matrix were polymerized by the sulfonic acid groups, thus forming an interpenetrating polymer network (IPN). These polymerizations and the diffusion of the D4 into the matrix were shown to be highly temperature dependent. Also, the D4 diffusion into the IPN seems to be augmented as the content of PDMS in the matrix increased. Subsequently, PDMS was homogeneously distributed throughout the SPE matrix, yielding a tough material with better mechanical properties than each of the polymer components, PDMS and SPE. Upon exposure of D4 to such a matrix, polymerization of the monomer continued along with gross phase separation with excessive swelling the IPN. Excessive concentration of PDMS, up to ca. 90 wt%, was easily incorporated through polymerization into the swelling matrix. Finally, the blister-like domains, up to 50 mum in diameter, containing pure high molecular weight PDMS (>1,000,000) have been observed when the polymerization continued. In another part of the research, functionalized cyclosiloxanes and polysiloxanes were synthesized by hydrosilylation of functional usd\alpha, \betausd-unsaturated esters. The hydrosilylation rate was dependent on the structure of both usd\alpha, \betausd-unsaturated ester and silicon hydride. The regioselective platinum-catalyzed hydrosilylation provided a versatile method for synthesizing functionalized siloxane monomers and polymers.
|
| Subject
|
:
|
cyclosiloxanes
|
|
|
:
|
Polymers
|
|
|
:
|
Pure sciences
|
| |