Study On Functionalized Star-shaped Integral Rubber SIBR Copolymer

During the last few years, with the development of lithium initiator in anionic polymerization and the improved requirement of low temperature resistance, wet skid resistance, low rolling resistance and good processability, cold flow property resistance and so on, functionalized multilithium initiator, which was increasingly attracted extensive attentions was an effective method to prepare functionalized star-shaped polymer.In the cyclohexane solvent, additional butadiene for improving solubility and tetrahydrofuran (THF) as polar additive for improving reacting speed the nitric functionalized multilithium initiator (N-M-Li) was prepared from commercial divinylbenzene (DVB) and hexamethyleneiminelithium (LHMI) that was preformed by the reaction of n-BuLi with hexamethyleneimine (HMI) in proper temperature. The initiator has the advantages of good solubility in non-polar solvent, fast initiating speed, single solvent system, simplified preparation technology, short synthesis time and low cost. The present thesis utilized the N-M-Li as anionic initiator to initiate the butadiene/isoprene/styene system and synthesized nitric functionalized star-shaped integral rubber (N-(SIBR)_n) and solution styrene-butadiene rubber (N-(SSBR)_n). Furthermore, this paper studied systematically the kinetic behavior and heat effect in the polymerization process. The microstructure, molecular weight and its distribution of the copolymers were also investigated in detail. In addition, the dynamic mechanical analysis, heat property and physical mechanical property ware well discussed. From the summary the full thesis, it came to the conclusions, as follow:1. The functionalized multilithiun initiator which had the featured of cheaper and easily available raw stuff and simple preparation technology was used to initiate the butadienen/styrene/isoprene and synthesized N-(SIBR)_n and N-(SSBR)_n. The study results showed that the initiator could be used to realize the design for molecular structure of copolymer and get the width distribution copolymer.2. The kinetic behaviors in the process of synthesis polymer, polymerization heat effect and the relationship between polymer composition and conversion at different polar additive dosage, different initiation temperature, different initiator concentration, different DVB dosage and different monomer proportion were studied. And the pseudo first order values under different conditions, the apparent activation energies under different initiation temperature and the polymerization rate equations of different monomers were obtained.3. The microstructure and Tg of N-(SIBR)n and N-(SSBR)n, which were attained at different experimental conditions, were measured via the methods of 'H-NMR, FTIR and DSC in detail. Whereafter, through the TGA and GPC the heat stability, molecular weight and its distribution were systematically investigated.4. The nitric functionalized star-shaped copolymers N-(SIBR)n and N-(SSBR)n were successfully prepared with functionalized multilithium as intiator for the first time at home and brode. The dynamic mechanical behavior and the mechanical properties of the two copolymers were investigated, and their mechanical properties were compared with the industrical and patent products in detital. The results showed that the copolymers were provided with high repel wet skid resistance, low rolling resistance, width MWD, well processing properity, and excellent mechanical properties integral rubber with good application value.