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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. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

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. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1–7, 2006

The rheological properties of hydrophilic fumed silica dispersed in polyethylene glycol (PEG) were investigated. The dispersion was prepared by dispersing the fumed silica in PEG with various concentrations. The reversible sol–gel transition was observed over 5 wt % of silica concentration as a function of temperature. The gelation temperature was found to depend on the applied shear stress and silica concentration, and the high shear stress was found to lead to the decrease of sol–gel transition temperature of the dispersion with the same silica concentration. As the silica concentration increases, the sol–gel transition shifts to the lower temperature. © 2006 Wiley Periodicals, Inc. J Apple Polly Sci 103: 2481–2486, 2007

This article describes the preparation and properties of unsaturated polyester (UP)/montmorillonite (MMT) nanocomposite by UV radiation. Benzildimethylketal and 1-hydroxy cyclohexyl phenyl ketone (HCPK) as a photoinitiator in UP were photolyzed under nitrogen condition. Analysis of X-ray diffraction patterns of the composites shows that the interlayer spacing of MMT is substantially increased. The type and amount of photoinitiator affects the level of improvement in mechanical properties, and our results suggest that HCPK is a more efficient photoinitiator of UP curing reaction. The interaction between photoinitiators and MMT should be considered to acquire the reinforcement effect of the dispersed MMT nanolayers. The properties of nanocomposite are dependent upon the amount of MMT. The effect of MMT concentration on thermal and dielectric properties is also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3609–3615, 2006

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. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 238–242, 2004

The complex shear modulus of immiscible polymer blends was measured by a frequency sweep experiment for polystyrene (PS)/low density polyethylene (LDPE) and poly(methylmethacrylate) (PMMA)/LDPE blends at constant composition (13.5/86.5 vol %) and compared with the prediction model of Palierne. Different morphologies of each blend were also prepared using a rheometer with a constant shear rate and different strain. There was morphological dependency on the complex shear modulus at constant temperature. However, this dependency disappeared at specific temperatures in the frequency sweep experiment. There seemed to be a specific temperature like critical flow temperature (Tcf) of amorphous polymer. The difference in morphology affected the complex shear modulus of blends below the specific temperature, Tcf, but did play a major role in determining the complex shear modulus of blends at over specific temperature. A new method may be needed to determine the critical flow temperature of an amorphous polymer via the measurement of a complex shear modulus for immiscible polymer blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 917–924, 2002

Barrier ribs in color plasma display panels (PDPs) function to maintain the discharge space between two glass plates as well as to prevent optical crosstalk. Patterning of barrier ribs is one of the unique processes for making PDPs. In this work, photosensitive barrier rib pastes were prepared by incorporating binder polymer, solvent, functional monomers, photoinitiator, and barrier rib powder. Studies of the function of the materials for the barrier rib paste were undertaken. After optimization of the paste formulation and photolithographic process, the barrier rib could be obtained with good resolution up to 110–120 μm height and 80–90 μm width. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2092–2099, 2002

Aromatic polyimides were synthesized from aromatic carboxylic acid dianhydrides, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), 4,4′-(2,2,2-trifluoro-1-phenylethylidene)diphthalic anhydride (3FDA), and pyromellitic dianhydride (PMDA), with four typical aromatic diamines. These included polyimide (PI) from 2,2-bis(4-aminophenyl)hexafluoropropane (4BDAP) by two-step procedures; amidation to polyamic acid (PAA), followed by thermal imidization of PAA. The chemical and physical properties of the newly prepared polyimides were compared in terms of their chemical structures, inherent viscosity, thermal property, transmission, dielectric constant, UV cutoff, water absorption, and refractive index. PIs 3FDA/4BDAP and 6FDA/4BDAP were soluble in common organic solvents, whereas others were not. In particular, it was found that the solubility was dependent on the temperature of imidization. The chemical and physical properties of the newly prepared polyimides derived from 3FDA were similar to the polyimides derived from 6FDA. The solubility of polyimide containing an ether functional group in the dianhydride moiety was better than that of the ether functional group in the diamine moiety. The polymers with ether linkage in dianhydride moiety exhibited lower glass transition temperature than their functionality-reversed analogous polymers with ether linkage in diamine moiety. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 38–44, 2002

Unsaturated polyester (UP) resin is one of the major thermosetting resins and is very useful as a matrix resin of composite material for its processibility. UP resin, however, has several shortcomings: it is weak in alkalis, volume shrinkage occurs during the crosslinking reaction of the oligomeric UP resin with a styrene monomer, and it is also brittle. The mechanical properties of UP resin can be enhanced by blending it with various materials. In this study, polyurethane (PU) was used as a modifier to improve the toughness of the UP resin. The effect of the polyol molecular weight as a PU soft segment and the PU contents on the toughness of PU-modified UP resins were studied. A UP/PU polymer network may occur through a reaction between an isocyanate group in the methyl diisocyanate (MDI) and a hydroxyl one in the UP molecules. The maximum toughness was observed at approximately 2 wt % of the PU content. These results can be rationalized by the incorporation of a rubbery PU segment into a brittle UP resin. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 735–740, 2002; DOI 10.1002/app.10169

Poly(ethylene terephthalate) (PET) texture was exposed to oxygen plasma glow discharge to produce peroxides on its surfaces. These peroxides were then used as catalysts for the polymerization of acrylic acid (AA) in order to prepare a PET introduced by a carboxylic acid group (PET-A). Chitosan and quaternized chitosan (QC) were then coupled with the carboxyl groups on the PET-A to obtain chitosan-grafted PET (PET-A-C) and QC-grafted PET (PET-A-QC), respectively. These surface-modified PETs were characterized by attenuated total reflection Fourier transform IR spectroscopy, electron spectroscopy for chemical analysis, and a contact angle goniometer. The amounts of AA, chitosan, and QC grafted on the PET surfaces as determined by the gravimetric method were about 6, 8, and 9 μg/cm2, respectively. The antibacterial activity of the surface-modified PET textures was investigated using a shake flask method. After 6 h of shaking, the growth of bacteria was markedly inhibited by PET with ionically (86% in PET-A−-C+) and covalently (75% in PET-A-C) grafted chitosan and with covalently grafted QC (83% in PET-A-QC). After the laundering the inhibition of the growth of the bacteria was maintained in the range of 48–58%, showing the fastness of the chitosan-grafted PET textures against laundering. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2769–2778, 2001

Prior to curing, we evaluated thermal stability of poly(butylene succinate) (PBS). Above 170°C, PBS was severely degraded and the degradation could not be successfully stabilized by an antioxidant. PBS was crosslinked effectively by DCP at 150°C, and the gel fraction was increased as DCP content increased. The major structure of crosslinked PBS is supposed to consist of an ester and an aliphatic group. The tensile strength and elongation of PBS were improved with increasing content of DCP, but tear strength was only slightly affected. The higher the crosslinking, the lower the heat of crystallization (ΔHc) and heat of fusion (ΔHf). However, the melt crystallization temperature (Tc) of crosslinked PBS was higher than that of PBS. The viscosity of crosslinked PBS increased and exhibited rubbery behavior as the content of curing agent increased. The biodegradability of crosslinked PBS did not seriously deteriorate. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1115–1124, 2001

It is found that miscibility of isotactic poly(methyl methacrylate/poly(vinyl chloride) blend improves as a function of plasticizer content and this miscibility enhancement is also affected by the chemical structure of the plasticizer

UV curable acrylic PSAs (pressure-sensitive adhesives) were modified with organic and inorganic flame retardants to improve flame retardancy of PSAs minimize the sacrifice of adhesion properties. The flame retardancy (UL-94 test) of acrylic PSAs were enhanced by the addition of 5–30 wt % of an organic flame retardant such as TCEP (Tris(2-chloroethyl)phosphate), PBPE (pentabromophenyl ether), and TBBPA(3,3′5,5′-tetrabromobisphenol A). Especially, TBBPA is the best flame retardant for acrylic PSAs when it works alone. However, PSAs compounded with aluminum trihydroxide (Al(OH)3) showed a little reduction in burning time up to 30 wt %. An apparent synergic effect was observed only for an acrylic PSAs with a combination of TCEP and PBPE flame retardants. The addition of flame retardants brought a no significant effect on curing even in high amount. It was surmised that the miscibility between PSAs and flame retardant was closely related with flame retardancy and adhesion properties of acrylic PSAs. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010