摘要:

AbstractImpact‐toughened, compatibilized binary blends of styrene‐maleic anhydride (SMA) copolymer/amine functionalized ethylene‐propylene (amine‐EP) polymer and ternary blends consisting of SMA/amine‐EP/high density polyethylene (HDPE) are described. In both blends 0.02 to 4 μm range rubbery inclusions, which toughen the SMA matrix, are formed. SMA sub‐inclusions exist in the amine‐EP phase. In the ternary blend substantially all of the polyethylene is embedded in the EP phase. Compatibilization of the SMA and the commingled polyolefin phase is promoted by a graft copolymer formed by the reaction of amine groups on the EP with the maleic anhydride groups on the SMA. We describe the morphology, rheology, aging characteristics and impact properties of these blends. SMA modification by SMA‐g‐(amine‐EP) polymers formedin situin the melt, with HDPE, has not been

ISSN:0032-3888    

DOI:10.1002/pen.760331202

出版商:Society of Plastics Engineers    

年代:1993

数据来源: WILEY

摘要:

AbstractThe polymers of the aromatic nitrogen compounds N‐methyl‐pyrrole (P‐N‐Me‐PPY), carbazole (PCarb), and aniline (PANI) have been investigated with electro‐optical and surface analytical methods. Thein‐situreflection spectra indicate the formation of polarons or bipolarons during electrochemical oxidation, depending on polymer type. The absorption bands can be attributed to changes in the electronic structure with regard to the applied potential. Photocurrent spectra of P‐N‐Me‐PPY and PCarb show a p‐type semiconducting behaviour for the polymers in the reduced state. The transition to the oxidized state with quasi‐metallic properties is indicated by a significant shift in the Fermi level energy and can be followed with X

ISSN:0032-3888    

DOI:10.1002/pen.760331203

出版商:Society of Plastics Engineers    

年代:1993

数据来源: WILEY

摘要:

AbstractAn experimental study of the effect of surface roughness and crystallinity on the light scattering of polyethylene tubular blown films is reported. Several films were prepared by varying the raw polyethylenes and the extrusion temperature. Other processing variables were maintained constant. We have made a statistical analysis of data and we have obtained multiple regressions between light scattering for a given wavelength of incident light and a given film thickness (30 μm, 50 μm, and 70 μm) and the independent variables average surface roughness and degree of crystallinity. It was demonstrated that, for the polymeric films studied, the surface texture evaluates better than crystallinity the variation of light scattering, but crystallinity has also some importan

ISSN:0032-3888    

DOI:10.1002/pen.760331204

出版商:Society of Plastics Engineers    

年代:1993

数据来源: WILEY

摘要:

AbstractThe deformation behavior of rubber toughened poly(methylmethacrylate), RT‐PMMA, has been investigated in terms of the ability of the material to nucleate plasticity. Work‐hardening rate parameterKmeasurements in the early stages of the nonelastic response in a constant strain‐rate test are used to probe the development of micro shear zones as a function of rubber volume fraction. The results reveal the existence of a sharp transition from difficult to easy shear band nucleation for a critical rubber volume fractionVc. This abrupt change in mechanical behavior also shows in the evolution of the critical stress intensity factorK I cmeasured at the onset of crack initiation. These findings are discussed in terms of the morphological parameters of t

ISSN:0032-3888    

DOI:10.1002/pen.760331205

出版商:Society of Plastics Engineers    

年代:1993

数据来源: WILEY

摘要:

AbstractBlends of a thermotropic liquid crystalline polymer (LCP), Vectra A900, and a thermoplastic elastomer, Kraton G1650, were made on a single screw extruder. During extrusion, fibers of the LCP are formed under influence of shearing and elongating forces. The stiffness and tensile strength of the elastomer are greatly improved by the addition of the LCP. The modulus of elasticity of blends containing up to 20% LCP can be described well with the Halpin‐Tsai equation. Differential scanning calorimetry and dynamic mechanical thermal analysis (DMTA) measurements show that the polymers are immiscible, but the DMTA results show a shift of the glass transition temperature of the elastomeric block of the Kraton polymer. This shift may be attributed to a layer of elastomer adsorbed on the LCP particle

ISSN:0032-3888    

DOI:10.1002/pen.760331206

出版商:Society of Plastics Engineers    

年代:1993

数据来源: WILEY

摘要:

AbstractThe high degree of electron delocalization in heterocyclic aromatic molecules makes this class of chemistry ideal for hyperpolarizability and NLO (nonlinear optics) polymer developments. This type of polymer is usually insoluble in common solvents and is not amenable to common optical film processing techniques like spin coating. A study of the approach in using an acidic solution extrusion followed by coagulation for optical quality film forming is reported in this paper. The polymers studied are: PBZT, (poly (p‐phenylene benzobisthiazole)); 6F‐PBO (polybenzobisoxazole containing hexaflorinated moities); and Zytel 330 (an amorphous nylon). Some of the resulting films showed an improved optical quality while others showed an extremely poor optical quality over the films used in a previous study. The optically clear films, however, were not of wave‐guiding quality. The defects in the films that would cause light scattering were characterized and the probable causes of these defects were discussed. The defects were: (a) optically inferior morphology, (b) micro‐voids, (c) macro‐voids, (d) solid particles, (e) lines in the transverse direction, and (f) lines in the machine direction. Identification and classification of these defects will help additional efforts in the future for improving the optical quality of heterocyclic aromatic poly

ISSN:0032-3888    

DOI:10.1002/pen.760331207

出版商:Society of Plastics Engineers    

年代:1993

数据来源: WILEY

摘要:

AbstractThe morphology developing during the spinodal decomposition process of polystyrene (PS)/poly(vinyl methyl ether) (PVME) blends was successfully controlled by photo‐crosslink reactions between PS chains. The crosslink reaction was carried out by taking advantage of the photodimerization of anthracene moieties that are labeled on PS chains. Effects of photo‐crosslinks on the morphology induced by temperature jumps (T‐jump) from the one‐phase region into the spinodal region were examined under several experimental conditions such as T‐jump depths and irradiation times. It was found that the concentration fluctuations developing during the spinodal decomposition process were efficiently frozen upon irradiation using a XeF excimer laser as well as a mercury (Hg) lamp. Furthermore, these ordered structures are quite stable upon annealing. These results demonstrate that the morphology developing during the spinodal decomposition process can be well controlled by easily accessible light sources such as high pressure mercury lamps. Thus the photo‐crosslink reaction described in this work can provide the basis for a potential technique to design multiphase polymer materials with controllable ordered

ISSN:0032-3888    

DOI:10.1002/pen.760331208

出版商:Society of Plastics Engineers    

年代:1993

数据来源: WILEY

ISSN:0032-3888    

DOI:10.1002/pen.760331201

出版商:Society of Plastics Engineers    

年代:1993

数据来源: WILEY