Unified Production of Chlorinated Isotactic Polypropylene and Chlorinated Paraffin Via a Solvent Free Chlorination Process

摘要

An environmentally friendly method for producing chlorinated isotactic polypropylene (CIPP) with chlorine percentage of 28-35, by weight is proposed, in which a reactive solvent, paraffin, is used to replace the commonly used inert solvent of carbon tetrachloride (CTC), an ozone depleting substance being phased out under the Montreal Protocol. This method utilizes the principle that paraffin can dissolve isotactic polypropylene (IPP) at about 150 C and the resulting solution can be chlorinated concurrently, forming two useful products, viz. chlorinated paraffin (CP) and CIPP, which are mutually soluble even at lower temperature, e.g., 70 C. The present method is superior to the conventional CTC solvent method because it can reduce the solvent emission dramatically, enhance the volume efficiency of reactor, and achieve a unified production of CIPP and CP under atmospheric pressure. The structure and properties of CIPP produced by two different methods are determined by differential scanning calorimetry, attenuated total reflectance-Fourier transform infrared spectroscopy, proton magnetic resonance (~1H-NMR), and ~(13)C-NMR. The results indicate that IPP chain can be homogeneously chlorinated in paraffin as in CTC solvent via a radical mechanism.