Natural rubber latex (NRL) is mainly used around traditional industrial products, but currently their target application is continuously expanding into tissue engineering. To broaden our knowledge of application in tissue engineering of NRL, we have for the first time examined the latex biocompatibility in vitro against a panel of cancer cells(A549, A2780, and MDA-MB-231). Owing to fractionation of NRL nanoparticles by ultra-centrifuge, the effect of the non-rubber constituents on the cytotoxicity was clarified. In addition, profound studies including cell cycle arrest abilities and apoptosis induction profiles against cancer cells were discussed in detail.

In order for NRL nanoparticles to be employed in tissue engineering, they need to have designed biological interaction with cells as well as favorable mechanical properties. Cells can delicately sense and respond to external nanoscale features in intricate living systems. With this in mind, an in-depth understanding of cell differentiation may bring a new perspective to tissue engineering including new bone regeneration and cartilage therapy.

This review summarized some reports and data concerning of thermal conductive polymer composites, by focusing thermal interface materials (TIM). Here, we explained 8 factors to affect thermal conductivity of polymer composites, before introducing various types of thermal conductive models. And I discussed the enhancing methods of thermal conductivity of polymer composites in last century, after explaining the progress in thermal conductive resin and fillers. Then, I explained the methods developed by focusing how conductive fillers were connected. Finally, present and future in TIM were discussed in the several types of viewpoints.

1. Hysteresis of stress-strain, SIC-strain, temperature-strain in un-vulcanized rubber and vulcanized rubber have been observed. The elucidation of the SIC phenomena should be applicable on these hysteresis. Temperature increase is a result of heat producing process of phase transition from amorphous to crystal, that is, latent crystallization heat. Therefore, temperature change is directly connected to SIC.

2. A new constitutive equation of stress-strain relation with inhomogeneous distribution of network chain, SIC and temperature change was proposed by Khiêm and Itskov. They succeeded to simulate a stress-strain relation of vulcanized natural rubber during loading and un-loading. They addressed that a creation of bundle-like SIC decreases the increasing stress during loading process and SIC may transform from bundle-like crystal to folded-chain crystal during un-loading process.

3. Rubber is composed of not only polymer chain but also solid particles and crystals such as zinc oxide, stearic acids, non-rubber components of NR and others. Therefore, rubber is very inhomogeneous material. During deformation, polymer matrix is deformed in-homogeneously, therefore, stress and strain distribute and concentrate at certain area. At these stress and strain concentrated area, void or crack might be occurred. SIC are created easily at such area because of high stress or strain. In such case, rubber is no more non-compressible material.

4. Shape memory phenomenon. After stretching 800% and keeping the sample for a few minutes, then release the sample, the sample shrink a little bit to 750% and keep the stretched state without any force. The phenomenon is a kind of shape memory. It must be a special relationship between SIC and networks. It may suggest us to try other deformation technique in order to characterize SIC phenomena.

Basic concepts and methodology of viscoelasticity are summarized. Then entanglement concept and nonlinear viscoelasticity of polymers having high molecular weights are discussed from the experimental viewpoints.