Modified Butyl Rubber By NaH/Carbonyl Compound And Studied On Its Mechanism

Because the special feature structure of molecular chain of butyl rubber leading it has many unusual properties different from other kinds of rubber. In order to extend the application scope of butyl rubber, meet the people’s need in the reality. In this paper, we taken sodium hydride(NaH) and maleic anhydride as activating agent and modifier respectively to modify butyl rubber in the rubber processing facility. The structure of the modified product was analyzed by FT-IR、GPC and 1H-NMR, at the same time the curing properties and mechanical properties were studied.It was found that molecular chain of butyl rubber changed little and the polar carboxylate functional groups and unsaturated carbon-carbon double bonds were introduced to the molecular chain successfully after the modified reaction. Increased the unsaturated and polar of IIR. From the comparison of curing properties and mechanical properties, we can conclude that the performance of IIR improved greatly after the modified reaction.For the first time using small molecule compounds a-pinene as model compounds to replace IIR to simulate the reaction of NaH/carbonyl compounds with butyl rubber, depicted the modification mechanism detailed. The modification process not only the addition reaction of double bond and substitution reaction of allylic hydrogen, and the reaction degree of substitution reaction is larger than that of addition reaction. The extent of reaction with the dosage of NaH increasing and reaction time increased, reaction degree have great changes with different carbonion acceptors added in. Showing the overall δ(2.17～2.22) hydrogen reaction most,δ(1.65) hydrogen area change rate,6(1.93) the area of hydrogen change the minimum. This variationis mainly affected by the reaction at the location of active hydrogen dissociation energy, activeallylic hydrogen atoms, the reaction stability of corresponding carbon anion and chemical shift of the proton steric effect.The experiment result shown that not only the double bonds but also the allylic joined in the modified reaction and the substitution reaction occured in a larger amount than that of the addition reaction. the reaction degree were different with different reaction time and different dosage of NaH, but arise an increase of reaction degree with the prolong of reaction time and the dosage NaH increased. The possible reaction of MAH was studied as well, founding that he molecular structure of the maleic anhydride has gone through a ring-opening reaction.This paper also researched the properties of modified butyl rubber changed when filled with various kinds of carbon black、white carbon black instead of carbon black partly. From the analysis of change of properties to determine the desirable filled amount of the filler.