To give properties of both high heat resistance and impact strength，which are required for Industrial components，to poly-L-lactic acid (PLA)，we sought to create a compound that includes an agent granting flexibility，a nucleating agent of proprietarily developed starch and poly-D-lactic acid. We also used natural rubber as a flexible phase，and epoxidizednatural rubber，which joins the flexible and rigid crystalline phases，and poly(carbodiimide) (PCDI) as a hydrolysis inhibitor and anadhesionbetween NR/ENR and PLA to create a new compound for injection molding that uses morethan 97% plant material. Compared to PLA itself，the　injection　molding　products obtained from the modified PLA compound (97% plant material) had an increased heat resistance of about 50℃ and 10 times greater impact strength from the evaluation of the impact and thermal mechanical properties of the compounds by JIS K7160 and JIS K7191-2Be. The physical improvements in PLA are due to the bonding of the uniformly distributed PLA crystalline phase by scanning probe microscopy. The effect of molecular weight of PCDI or amount of PCDI added was also examined on their mechanical properties or PLA crystallization rate.

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Effects of molecular structure on adhesion properties and phase structure of polystyrene-block-poly (ethylene-co-butylene) -block-polystyrene triblock copolymer (SEBS) were investigated. Forthis purpose，six kinds of SEBS were used: standard with 20 wt% of polystyrene block content and higher hydrogenated degree (A)，that with 13 wt% of polystyrene block content (B)，that with lower hydrogenated degree (higher residual butadiene unit in middle block，C)，that with maleicanhydride group in middle block (D)，that with short polystyrene units distributed randomly in middle block(E) and that with 30 wt% of polystyrene block content and one polystyrene block end is terminated with amino group (F). The observed phase structure by a transmission electron microscopy was a mixture of spherical domain and cylindrical structure for A-E. It was a mixture of cylindrical and lamellar structures for F，because F has higher cohesive strengh of polystyrene block by the introduction of amino group. B and D showed the higher peel strength and tack than A. B showed the highermolecular mobility because of the higher middle block content. D showed the higher interfacial adhesion by the incorporation of maleic anhydride group in middle block.

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Oil is one of the most valuable and important resources for us.How to extend the Reserves-toproduction(R/P)ratio is a great challenge to current technologies.However,today,we recover only about 30% of oil from reservoirs,and there is still untapped oil in the deeper,hotter reservoirs.The technology for High Pressure High Temperature(HPPIT)seals is the most important development to access this untapped oil.The target of this study is to improve the production ratio by developing HPHT seal material for the deeper and hotter reservoirs. Many new research projects focus on improving the mechanical properties of CNT/rubber composites,but few of them have succeeded because of the dispersive and adhesive issues of CNT.This research paper introduces new technology based on the heating and surface oxidizing of CNT,to solve the adhesion issue between CNT and FKM rubber.By optimizing the oxidizing process,the connection between CNT and FKM is more stable against high temperature attacks.A longer connection strand enables an increased elongation by a carbon-oxygen-polymer chain.This high performance seal is the first of its kind in the oilfield using CNT/rubber composite technology.

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Composite　adhesives　composed　of　emulsion　pressure　sensitive　adhesive(Em-PSA)andsingle-walled carbon nanotubes(SWCNT) were fabricated,and the relation between the electrical conductivity and the particle size of the emulsion was investigated.The dispersibility of SWCNT in water media was enhanced by combined use of two dispersants, carboxymethyl cellulose sodium salt and rutin.The transmission electron microscope image showed the wrapping of dispersants around SWCNT,which leads to high dispersitivity of the SWCNT in the composites.The surface resistivities of the composites with fixed SWCNT content(0.44phr) were 5.34×10⁹Ω/□,2.57×l0⁵Ω/□,1.43×10⁵Ω/□with the increase of particle size 157nm,326nm and 454nm,respectively.In case of larger particlesize,the existing density of SWCNT became larger in the interparticle layer,which resulted in higher electrical conductivity.

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