Multipoint covalent immobilization of enzymes (through very short spacer arms) on support surfaces promotes a very interesting 'rigidification' of protein molecules. In this case, the relative positions of each residue of the enzyme involved in the immobilization process have to be preserved unchanged during any conformational change induced on the immobilized enzyme by any distorting agent (he...

PURPOSE Shrinkage of resinous die materials during setting reaction limits their acceptance, even though these materials show several advantages compared to stone die materials with respect to strength, abrasion resistance, and detail reproduction. The purpose of this study was to determine if retarding the setting reaction during polymerization and altering the base-to-catalyst ratio, as sugge...

In this article we introduce and compare three techniques for low-cost and rapid bonding of stereolithographically structured epoxy components to polydimethylsiloxane (PDMS). In short, we first create a polysiloxane layer on the epoxy surface via silane surface coupling and polymerization. Afterwards, the modified epoxy surface can be bonded to a PDMS component at room temperature using a handh...

A well-dispersed phase of exfoliated graphene oxide (GO) nanosheets was initially prepared in water. This was concentrated by centrifugation and was mixed with a liquid epoxy resin. The remaining water was removed by evaporation, leaving a GO dispersion in epoxy resin. A stoichiometric amount of an anhydride curing agent was added to this epoxy-resin mixture containing the GO nanosheets, which ...

In the present research work, the flexural modulus and strength of glass fiber-epoxy resin and carbon fiber-epoxy resin composites have been enhanced through fiber tension during curing of the polymeric resin. This study showed that the tension applied on the fibers increased the flexural modulus of the glass-epoxy composites up to 12% and the flexural strength up to 19%. The flexural modulus a...

Bismaleimide (BMI) resins are developed very rapidly due to the demands of the defense and aerospace industries. They are cross-linked polymers which process like epoxy resins but have an upper use temperature of 230°C, compared to the epoxy upper use temperature of 175°C. Also due to the available intrinsic properties of BMI resins such as higher thermal stability and lower toxicity than those...

Biocatalyst mediated regio- and stereo-selective hydroxylation and epoxidation on (Z)-α-santalol were achieved for the first time, using a fungal strain Mucor piriformis. Four novel metabolites were characterized as 10,11-cis-β-epoxy-α-santalol, 5α-hydroxy-(Z)-α-santalol, 10,11-dihydroxy-α-santalol and 5α-hydroxy-10,11-cis-β-epoxy-α-santalol. Using Amano PS lipase from Burkholderia cepacia, α- ...

We report the fabrication of and investigations into the dielectric and thermal properties of epoxy/boron nitride nanotube (BNNT) composites. It was found that BNNT fillers can effectively adjust the dielectric constant of epoxy. Moreover, the thermal conductivity of epoxy was improved by up to 69 % with 5 wt % BNNTs. Our studies indicate that BNNTs are promising nanofillers for polymers, to ob...

Epoxy resins are used widely in industry because of their strong adhesive properties, chemical resistance, mechanical toughness and high electrical insulation. Consequently they are often found in adhesives, stabilizers, sealants, varnishes and paints. Epoxy resins consist of bridged diepoxide oligomers of increasing molecular weight and there are various types corresponding to different molecu...

A low concentrated polystyrene (PS) additive to epoxy is used, since it is able to reduce the curing reaction rate but not at the cost of increasing viscosity and decreasing glass transition temperature of the curing epoxy. The modified epoxy is cocured with a compatible thermoplastic interleaf during the vacuum assisted resin transfer molding (VARTM) to toughen the interlaminar of the composit...