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Ethylene - tetrafluoroethylene copolymer (ETFE) is a fluoropolymer both excellent chemical resistance, high temperature resistance, weather resistance and other properties and processing characteristics of polyethylene thermoplastic high-performance engineering plastics. Synthesis and structure of domestic ETFE control technology, ETFE structure / property relationships less, ETFE production and processing of applications is still rather lacking. In this paper, the development of domestic ETFE, ETFE structure and properties for research, the establishment of ETFE composition, average molecular weight and molecular weight distribution measurement methods, and commodity and pilot ETFE thermal transition, crystallization behavior and rheological properties of a study. Characterization of ETFE composition for conventional instruments, the average molecular weight and molecular weight distribution difficulties, the establishment of quartz oxygen flask combustion - Ion Chromatography ETFE composition, dynamic rheological analysis characterize the average molecular weight and molecular weight distribution of ETFE method. According Carreau-Yasuda equation by the dynamic complex viscosity - frequency relationship fitting ETFE zero shear melt viscosity, and thus obtain the weight average molecular weight, weight average molecular weight was established ETFE (M w ) and The melt flow rate (MER) relational MFR = 2.16 × 10 12 M w -1.93 ; generalized Maxwell model fitting dynamic modulus quantity and frequency relationship, get plateau modulus G n 0 ; according viscoelastic theory, by G N 0 calculate M w -ω correlation coefficient K 2 ((?)) a new method by which the dynamic modulus - frequency relationship to calculate the average molecular weight and molecular weight distribution provides the foundation. According to the ETFE calculated X-ray diffraction curve of the crystal structure parameters, found that when the TFE mole fraction of less than 50%, ETFE is tetragonal crystal structure; TFE molar fraction of 50% -75%, the change in whichever hexagonal lines; TFE mole fraction of greater than 75%, ETFE having a rhombohedral crystal; when TFE molar fraction of 48% -75% of the, ETFE TFE crystallinity with increasing mole fraction of little change, crystal size slightly. Using differential scanning calorimetry (DSC) obtained by the polymerization of the resin and the secondary crystallization ETFE ETFE powder of the crystal melting behavior was found to increase as the molar fractions of TFE, binary ETFE powder before the melting temperature of the resin increases, TFE molar when 53% of maximum value, then the melting temperature lower mole of TFE was 65% when the minimum value of the melting temperature and subsequently increased. ETFE resin melting enthalpy is content with TFE first increases and then decreases. As a result of overheating of the heating rate increases and thermal imbalance ETFE secondary crystallization and melting enthalpy of the melting temperature increased with increasing heating rate. Obtained at different cooling rates of the secondary crystals melting temperature of ETFE little difference, the cooling rate as the melting enthalpy decreases. Different annealing temperature and time to deal with the melting curves of ETFE multiple melting peaks. ETFE studied the non-isothermal crystallization kinetics, found that as the cooling rate increases, the undercooling increases, ETFE crystallization temperature T p gradually decreased, the crystallization temperature range widened. Processed by the modified Avrami equation crystallization kinetics found ETFE nucleation stage crystallization process into by the nucleation stage and the spherulites spherulites and grow in three stages, the process consists of a polarizing microscope observation has been verified. Mo Zhishen France (lgφ = lgF (T)-a × lgt) for ETFE non-isothermal crystallization kinetics of the process, a calculated value remained unchanged, while the F (T), along with the increase of the degree of crystallinity increases; With the mole fraction of TFE copolymer increases, ETFE non-isothermal crystallization activation energy increases. By rheological properties of ETFE, found that as the shear rate increases, ETFE melt shear stress increases, the apparent viscosity decreases, showing the shear-thinning; as the temperature rises, ETFE Melt closer Newtonian fluid; ETFE melt flow activation energy with shear rate increases. Studied the mechanical properties of ETFE secondary crystallization, found that as the heat treatment temperature, ETFE elongation at break, Young's modulus and bending modulus gradually increased, the tensile strength, bending strength and impact strength increases after the first decrease; at 230 ℃ for the heat treatment temperature, the heat treatment time is extended, ETFE elongation at break, flexural modulus, flexural strength and impact strength increased, the tensile strength and Young's modulus becomes smaller. These results on the synthesis and processing of ETFE has certain guiding significance.
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