摘要：
Natural Rubber (NR) is an important strategic raw material for manufacturing a wide variety of industrial products. NR has been mainly obtained from Hevea brasiliensis. The USA is self-sufficient in the production of synthetic rubber while NR supply in USA is mainly imported from Southeast Asia. However, synthetic rubber cannot match the performance of imported Hevea NR. It is a matter of great concern that the USA is highly vulnerable to disruptions of NR supply because of a possible introduction of leaf blight into plantations as none of the trees in plantations across Southeast Asia have resistance to blight. Puskas et al. postulated that the biosynthesis of polyisoprenoids in general, and that of NR in particular, may proceed by a living carbocationic polymerization process. “Natural living carbocationic polymerization” (NLCP) mechanism was proposed in terms of accepted polymer chemical formalism, i.e., initiation, propagation, and equilibria between active and dormant species. This thesis studied the fundamental steps of NR biosynthesis in two ways: 1) characterization of NR from stabilized latex and in vitro biosynthesis; 2) addition of isoprene (IP) and other derivatives to shift the enzymatic equilibrium of the terpenoid biosynthesis lifecycle. Synthetic initiators to be used in in vitro NR biosynthesis system were prepared and characterized. For the first portion of this thesis, in vitro NR biosynthesis was studied using high resolution size exclusion chromatography (HR-SEC). Then, various compounds such as isoprene (IP) and amylene were introduced to the in vitro NR biosynthesis system. The rationale behind these studies was based on the terpenoid biosynthesis lifecycle. HR-SEC, gravimetric analysis, in situ Raman spectroscopy and NMR spectroscopy were used to study scenarios where the equilibrium was disrupted by the introduction of foreign chemical compounds. The second goal of this research was to design and synthesize a synthetic initiator for the futu
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