| This thesis contains two parts:The frist part is the preparation of high gas barrier property of rubber material.Recently the nanocomposites have attracted many researchers' interest, but many practical problems desiderated to solve. For example, the gas barrier property of the rubber material does not meet requirements of tire inner tube and inner liner, and in some fields, such as aerospace, aircraft, and high vacuum systems, the extremely high gas barrier are demanded. The primary advantage of rubber/clay nanocomposites, especially with exfoliated morphology, is dramatic improvement in gas barrier properties, and at the same time, obtaining outstanding mechanical performances.Isobutylene-isoprene rubber (IIR) and halogenated butyl rubbers (XIIR) have the best gas barrier property among the general rubbers. It is expected that dispersing nano clay layers in (X)IIR matrix should effectively reduce the gas permeability. To authors' knowledge, however, not much work has been done to improve barrier performance of (X)IIR/clay nanocomposites, although the potential for commercialization of such a nanocomposite is expected to be high in the rubbery industries.The research works focus on the methods of preparation IIRCN, and the relationship of the structure and properties.(1) Preparation and properties of S-IIRCN and M-IIRCN.Compared with corresponding micro-composites and pure IIR vulcanizate, the prepared nanocomposites exhibit outstanding mechanical performances and excellentgas barrier properties. The aspect ratio of nano clay layers in S-IIRCN is larger than that of in M-IIRCN, which is probably the reason that S-IIRCN has better mechanical and gas barrier properties.(2) Preparation and properties of XIIRCN.XIIR/organic modified clay nanocomposites were prepared by melt intercalation. XIIRCN exhibit outstanding mechanical performances and improved gas barrier properties. This makes it possible for XIIR to be used as some products which require high gas barrier property, i.e., no inner- tubes tire and pneumatic tire.(3) Preparation and properties of IIRCN by swollen orgnomontmorillonite and shearing mixed with IIR.A new approach to obtain high gas barrier property and excellent mechanical performances for IIRCN was proposed. It is a method can sum up the advantages of solution and melt intercalation.Secondly, microstructural changes of RCNs induced by post processing are investigated.The changes of microstructures of RCNs during vulcanization are investigated. Some guidelines are put forward to obtain a desired morphology.The properties of composites are correlated with its structure. Consequently, it is of great important to well understand RCNs' structures in order to obtain information for their applications in industry.The exfoliated structure is the most interesting because of the greater clay-polymer interaction, which makes the entire surface of the clay available to a polymer. This causes maximum changes in the mechanical and physical properties. But there has been little report about the desirable exfoliated morphology in rubber matrix can be achieved.Practical rubber products are generally made via vulcanization at above 130℃ at pressure, during which the intercalated structure may be changed due to flexible rubber macromolecules moving into or out of the clay layer space. Whether parameters of curing process influence the intercalation? What is the mechanism behind it? Clarifyingall these is important to explore both the scientific meaning and potential industrial application of polymer melt intercalation. To authors' knowledge, however, there has been no systemic investigation and well-accepted cognition on the effects of parameters of curing process on microstructures of RCNs up to date.How to achieve the dispersion of nano clay layers in rubber matrix and keep the ideal dispersion state of clay layers in rubber matrix (i.e., exfoliated structure) to rubber products, it is a key issue for RCNs.The research works focus on the influence of parameters of curing process, preparation methods and polarity of matrix rubber on the microstructures of some RCNs.(1) The changes of microstructures of uncured RCNs and RCNs cured at high pressure.The intercalated structures and their spatial distributions in the matrix are extensively altered by vulcanization, whether RCNs is prepared by various methods or various matrix rubber. It was first discovered that the curing pressure is the critical factor determining final microstructures of cured RCNs.(2) The effects of heat and pressure on intercalated structures of M-IIR/clay nanocompounds.The thermal treatment at air pressure (AP) can cause a transformation from the original intercalated structure to a new intercalated one with smaller gallery height, and partially-intercalated silicates which is transformed to un-intercalated silicates. Both increasing treating temperature and prolonging treating time can increase the extent of this structural transformation. Exerting extra pressure during thermal treatment can cause the further collapse of the intercalated structures and assembling of intercalated silicates.(3) The micro-structural changes of S-IIR/clay nanocompounds induced by heating and extra pressure.Annealing S-IIR/clay nanocompounds at low temperatures (i.e., 80-130℃) favors the formation of intercalated structures, but annealing at high temperatures (i.e.,...
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