ABSTRACT:The morphology of nylon 6 and polystyrene (PS) blend with styrene-maleic anhydride copolymer (SMA) as a compatibilizing agent was studied. The long-time mixing of blends exhibited slight decrease in storage modulus and larger domain size. This may be caused by imidization between amine end-group of nylon 6, and SMA produce the water, which hydrolyzes an amide group of nylon 6 and results in the decrease of viscosity. As the morphology change in blend influence on physical properties, it is found that modification of nylon 6 by SMA has a better morphology and good physical properties with shorter mixing time.However, the morphology investigation in nylon 6/PS blends reveals that the effect of mixing time was negligibly small. Addition of small amount of SMA into nylon 6/PS blend has proved to give improvement in physical properties. This behavior is based on the concentration of water derived from imidization.
The influence of the montmorillonite type and concentration on the mechanical properties and morphology of a carboxyl-terminated butadiene acrylonitrile toughened epoxy/montmorillonite nanocomposite has been studied. Modified montmorillonite can be well dispersed in a carboxyl-terminated butadiene acrylonitrile toughened epoxy/montmorillonite nanocomposite. Jeffamine, a curing agent, contributes to the intercalation of sodium montmorillonite, allowing the loss of the ordered layered structure in the nanocomposite. The preparation method of the nanocomposite has a slight effect on the mechanical properties.
Unsaturated polyester (UP)/montmorillonite (MMT) nanocomposite was prepared by using hydroxypropylacrylate (HPA) as a reactive diluent instead of conventional styrene monomer and the effect of polarity of reactive diluent on properties of nanocomposite was investigated. X-ray and mechanical test data indicated that mixing for an extended period of time is essential to enhance the physical properties of nanocomposites in the UP/Cloisite 6A system. This was attributed to the high polarity of HPA that may disturb the preintercalation of UP resin into the galleries of MMT.
ABSTRACT:The thermal stability and adhesion properties, such as lap-shear strength of hot-melt adhesives were obtained from amorphous poly(a-olefins) and thermoplastic rubber [styrene-ethylene-butylene copolymer (SEBS)] blends. The addition of SEBS increased the toughness and viscosity and decreased the lap-shear strength of the hotmelt adhesive. Terpene tackifier resin offered enhanced lap-shear strength; this was more effective when combined tackifier resin was added on the hot-melt adhesive. Only a small amount of wax and antioxidant affected the thermal stability and lap-shear strength of the hot-melt adhesive.
Pressure sensitive adhesive (PSA) based on 2-ethylhexyl acrylate (2-EHA)/acrylic acid (AA) copolymer was synthesized using different photoinitiators. Results showed that PSA with Irgacure ® 651 (benzyldimethylketal) and Irgacure ® 184(1-hydroxy-cyclohexylphenyl ketone) proved to be good for adhesion properties. This may be attributed to strong absorption near 350 nm wavelength and also high solubility in monomer mixtures. The addition of Irgacure ® 819, bisacylphosphine oxides as a photoinitiator caused cohesive failure with high loading in a peel test owing to the additional radical formation. It is assumed that the insoluble photoinitiator reacts with oxygene, which may act as a hydrogen donor.
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