| Summary: | 碩士 === 東海大學 === 化學工程學系 === 89 === Moisture cross-linking has been used successfully for Polyethylene (PE) since the 1970s, and the crosslinked products are often used commercially. Crosslinking has been an effective way to improve PE's mechanical properties , we therefore wish to moisture crosslink PVC such that a good result may be obtained like PE.
Experiment can be separated into grafting step and moisture cross-linking step. The reaction of PVC with aminosilane yielded silane-grafted PVC that can be cross-linked in hot water. The best cross-linking condition was determined by gel content. The grafting conditions included high temperature blending and low temperature blending. Low temperature blending can avoid degradation such that moisture crosslinking reaction can be more successful because more aminosilane was added. Resulting gel content is 80% and 90% in hot water 85℃ and 95℃ separately, which is close to 100%. Because of moisture cross-linking, thermal mechanical properties were greatly improved, both storage and loss modulus were much higher.
The kinetic study was carried out by swelling PVC with THF. The crosslinkung density was estimated with Flory-Rehner equation and the kinetic parameters such as the reaction order, rate constant and activation energy were decided by determining change percent of moisture cross-linking.
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