| 摘要 |
A novel chlorinated poly(vinyl chloride) ("CPVC") resin is prepared by a two-step process which uses an organic peroxide catalyst rather than a source of actinic light. The novel two-step "photoless" process yields a CPVC ("two-step CPVC") which, even at 72% Cl, is easily fusible at 170 DEG C. It is now possible to extrude and injection mold parts with exceptional heat distortion properties attributable to the higher Cl content of the resin. The key distinguishing characteristic over a CPVC made in the presence of a distinct liquid chlorine phase, which CPVC is the most closely comparable CPVC, is when lines are drawn connecting points for measured Tgs as a function of Cl content, for each type of CPVC. The slope of a line for two-step CPVC is about 15% less than the slope of a line for CPVC produced by a process in which excess chlorine is present as a distinct liquid phase. Further, the slope of the line for the two-step CPVC is about 40% greater than that of a line for CPVC produced in an aqueous photochlorination process. CPVC made by a solution polymerization process is identified by its characteristic bulk density, morphology and NMR spectra for mole %CCl2, mole %CHCl and mole %CH2, each as a function of NMR %Cl.
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