Studies On Solution Properties And Ultrasonic Degradation Kinetics Of Chlorinated Polypropylene

Due to good integrate properties, polypropylene(PP) has been widely used in industry and our daily life. The adhesion property of chlorinated polypropylene(CPP) to PP is better than other coating resins. Therefore, the abroad application of PP turns into the impetuses to study the properties of CPP.Aim at the weakness of CPP property research at present, systemic studies to volume properties, viscosity properties, solubility parameter and other thermodynamic properties as well as ultrasonic degradation kinetics of CPP were carried through in the thesis. These studies have a great science and applied significance for CPP.The CPP was separated into five fractions using fractional precipitations by solvent/nonsolvent technique. Densities for binary mixtures of five fractionated and unfractionated CPP which contains a mass fraction of 30 % chlorine with solvents were determined. At a fixed temperature, concentration and solvent, the densities for binary mixtures of fractionated and unfractionated CPP with solvents have the same value. The width of molecular weight distribution of CPP does not affect the densities of these mixtures. Based on this, the apparent molar volumes, standard partial molar volumes and partial molar volumes of CPP repeat unit have been calculated. Comparing with the molecular volumes of solvents, the repeat unit structure of CPP, C₆H₁₁Cl, has been determined. This result supplies valuable data for Flory-Huggins lattice theory.Densities for binary mixtures of CPP which contains a mass fraction of 30 % chlorine with toluene, tetrahydrofuran, chloroform, carbon tetrachloride, xylene and 2-butanone were determined at temperatures from (298.15 to 318.15) K. This systemic data supply basic data for project design and research of CPP.The viscosities of binary mixtures of CPP with solvents at 1%, 2%, 3%, 4%, 5% and 10% concentrations were measured using Ubbelohde capillary viscometer. It was found that all mixtures showed Newtonian flow. The effects of concentration, temperature, and molecular weight on viscosity have been studied. Flow activation energy of CPP solution was calculated in the experimental temperature range. These results offer references for selection of flow conditions and study of interaction between molecules.Ultrasonic irradiation was carried out for CPP toluene solutions at five concentrations. CPP with low molecular weight was obtained. The molecule structure, the chlorine content and the configuration of molecules in toluene solution don't change. This indicates that the molecules of CPP break at carbon-carbon bond. Molecular weight and intrinsic viscosity of degraded CPP were measured. It is found that the Mark-Houwink equation,[η]=0.017M^0.6919, is also suitable for degraded CPP. Its application range is enlarged.Relative solubilities of CPP with different molecular weights were determined by weighing method at 298.15K. A new standard for judging good and poor solvents of CPP was proposed. The results obtained by the proposed standard are consistent with reality, the standard of complete miscibility suggested by Flory-Huggins and the standard proposed by Hansen, Lieberman,Funasaka. According to the standard proposed here, the three-dimensional solubility parameters and the total solubility parameter of CPP acquired by optimization calculation were calculated. They were verified by the turbidity method. The effects of temperature, concentration, interaction parameter between polymer and its solvents on dissolution of polymer were discussed from thermodynamic point. The three-dimensional solubility parameters add a new content for thermodynamic data of CPP and offer reference for selection of its solvents.The limiting molecular weight and rate coefficient under ultrasonic irradiation could be obtained by data fitting technique. It was proved that the method was feasible by experiment. The fitting accuracy of common kinetic equations of polymers under ultrasonic irradiation for experimental data of chlorinated polypropylene was evaluated. It was found that the fitting results of these kinetic equations for experimental data of chlorinated polypropylene were not satisfactory. Therefore, a new second order kinetic equation for ultrasonic degradation was proposed: 1/(M_t-M_lim)-1/(M_o-M_lim)=kt. Ultrasonic degradation of CPP toluene solution obeys this equation. The effect of concentration on rate coefficient and limiting molecular weights was investigated. This equation is a new complement for ultrasonic degradation kinetics of polymers.General applicability of the common and new kinetic equations kinetic equations were verified by the 41 sets of available original ultrasonic degradation data of polymers collected from previous reports. It was found that the general applicability of the first and second order kinetic equation proposed in this work were wider than other equations. They can substitute the other equations completely. Then a general power law expression(GPLE)of ultrasonic degradation,-dM_t／dt=k(M_t-M_lim)ⁿ n=1 or 2, was suggested. The kinetic equations can be united by the GPLE.