摘要:

AbstractNotched Charpy impact strengths of a series of plasticrubber two‐phase polymer systems were measured over a wide range of temperatures. Blends of polyvinylchloride and rubbers with varying chemical structures, and several ABS polymers were investigated.In all systems, Charpy impact strength began to increase near the Tgof the rubber component followed by a logarithmic increase with increasing temperature. The trend is expressed by the following empirical relation:\documentclass{article}\pagestyle{empty}\begin{document}$$ I{\rm = }A{\rm exp(- }B/T{\rm)} $$\end{document}whereIis Charpy impact strength, A and B are constants, andTis the absolute temperature. This equation is applicable between the Tg's of the plastic and the rubber components. The increasing tendency of impact strength, i.e. theBvalue of the above equation, is depressed mainly by the decrease of the compatibility and/or the interfacial adhesive force between the two phases. Toughening mechanism and the ways of increasing toughness are discussed based on the craze formation mechanis

ISSN:0032-3888    

DOI:10.1002/pen.760100502

出版商:Society of Plastics Engineers, Inc.    

年代:1970

数据来源: WILEY

摘要:

AbstractYield stress (σY) and elongation to break (εb) were measured over a wide range of temperature under three different strain rates (\documentclass{article}\pagestyle{empty}\begin{document}$ \dot \varepsilon $\end{document}) for a series of polyvinylchloride‐rubber blends, ABS polymer and high‐impact polystyrene. It was found that a temperature‐strain rate reduction was possible for σYand the composite curve obtained by the superposition was expressed by the following relation:\documentclass{article}\pagestyle{empty}\begin{document}$$ \sigma _{\rm Y} = K_1 + K_2 \log \dot \varepsilon A_T $$\end{document}whereK1andK2are the material constants, andATis the shift factor.As for εb, a new maximum was found at around room temperature in addition to the known maximum at around the glass transition temperature of the matrix phase. The results are discussed in terms of the craze theory for rubber toughening of

ISSN:0032-3888    

DOI:10.1002/pen.760100503

出版商:Society of Plastics Engineers, Inc.    

年代:1970

数据来源: WILEY

摘要:

AbstractThe extursion melting model of Tadmor et al. (1967) has been modified to include the effects of screw channel curvature and melt leakage through the screw flight‐barrel clearance. An alternate coordinate system was used in modifying the model to simplify the addition of curvature corrections. Also proposed is an improved method of computing solid bed velocity. A substantial number of typographical errors and truncations appeared in the original data published by Tadmor et al., and verification of their computations with corrected data was successful in all cases. Channel curvature corrections and the improved method of computing solid bed velocity increased the predicted rate of solid bed width decrease by approximately 14% during the initial stages of melting. Addition of leakage flow to the model tended to offset this effect completely or in part. Leakage flow effects always predominated during the later stages of melting, however. These effects may interact differently for other extruder sizes or screw designs; therefore, the modified melting model should be a more accurate model for use in the design of extruder screws and in studies of extruder performanc

ISSN:0032-3888    

DOI:10.1002/pen.760100504

出版商:Society of Plastics Engineers, Inc.    

年代:1970

数据来源: WILEY

摘要:

AbstractThe residence time distribution (RTD) functions were derived for screw extruders, based on the “parallel plate” and curved channel flow models. The results indicate a relatively narrow distribution, and they explain several characteristics of screw extruders. The strain distribution in the fluid across the channel was also derived. With the aid of these two functions an average strain of the fluid leaving the extruder was defined. The resulting weighted‐average total strain (WATS) provides a quantitative criterion to the “goodness of mixing” in

ISSN:0032-3888    

DOI:10.1002/pen.760100505

出版商:Society of Plastics Engineers, Inc.    

年代:1970

数据来源: WILEY

摘要:

AbstractThe dynamic mechanical properties of blends of polymer melts were measured using the orthogonal rheometer. Two‐phase blends, polyethylene‐polystyrene, polyethylene‐poly‐(methylmethacrylate), and polystyrene‐polymethylmethacrylate, were studied. The in‐phase and out‐of‐phase moduli were measured over the range of composition and at frequencies between 10−4and 10 revolutions/sec.The out‐of‐phase modulus increases in a monotonic manner with composition. The in‐phase modulus, however, shows a maximum with composition in two cases. Examination of the relaxation spectra of these blends shows that when no maximum occurs it can be written as an additive function of the spectra of the components. In the case where a maximum is observed in the modulus the measured spectrum of the blend is shifted in frequency relative to the calculated one. This is tentatively attributed to slight interpretation and solubility of one phase in t

ISSN:0032-3888    

DOI:10.1002/pen.760100506

出版商:Society of Plastics Engineers, Inc.    

年代:1970

数据来源: WILEY

摘要:

AbstractThe dynamic elastic moduli were measured on macroscopic models simulating two‐phase microstructures where the second phase was present as a continuous, isotropic network. Using open‐pore polymer foams with higher‐moduli, infiltrating matrices, the composite moduli were found to be linear with volume fraction of the network phase. Variations of network cell size or surface area indicated that the moduli increased with increasing interfacial area, but only when interphase wetting was present and matrix contraction upon solidification occurred. Metallic foams with a lower moduli matrix produced moduli that were compatible with existing bounding theories for compo

ISSN:0032-3888    

DOI:10.1002/pen.760100507

出版商:Society of Plastics Engineers, Inc.    

年代:1970

数据来源: WILEY

摘要:

AbstractThe use of a commercially available thermomechanical analyzer (TMA) operated in its isothermal mode is illustrated for studies of polymer‐swelling and dissolution in liquids. Results for a variety of polymer‐swelling agent systems demonstrate that information usually requiring more sophisticated experimental techniques can be readily obtained with the TMA. In particular rates of swelling and penetrant diffusion coefficients can be determined for selected systems. Dissolution measurements, exemplified here for polystyrene in three different solvents, can be utilized to obtain steady state rates of solvent penetration and rough estimates of the interdiffusion coefficient for a system. The experimental limitations involved in both types of measurement are discus

ISSN:0032-3888    

DOI:10.1002/pen.760100508

出版商:Society of Plastics Engineers, Inc.    

年代:1970

数据来源: WILEY

摘要:

AbstractThe use of a commercially available thermomechanical analyzer (TMA) operated in its isothermal mode is illustrated for studies of penetration of a hemispherically‐tipped probe into a material sample. Two amorphous copolymers were studied at various temperatures above their softening points. Kinetics of penetration are compared with tensile creep measurements for these viscoelastic materials. A simple semi‐empirical relationship between creep and penetration at small strains is applied and found to yield approximate although not exact agreement with experiment. It is thus possible that for homogeneous materials of this type creep data might be easily predicted with a fair degree of accuracy from penetration data and vice versa. Experimental problems involved in the TMA penetration technique are discus

ISSN:0032-3888    

DOI:10.1002/pen.760100509

出版商:Society of Plastics Engineers, Inc.    

年代:1970

数据来源: WILEY

摘要:

AbstractA statistical study was conducted to determine the significance of the sources of variability in the laboratory (carbon arc) weathering of a light‐stabilized polyester resin system. Color fastness of the resin was evaluated in terms of changes in total color, lightness, and chromaticity. Factors that significantly influenced the results were variability within castings and between batches of resin, location of the specimen within the exposure apparatus, and the storage time prior to testing. The carbon arc instrument provided a relatively insensitive test for evaluating a light‐stabilized polymer system, chiefly because, with a stable polymer, small random variations in response become almost equal to the small change in color developed on expos

ISSN:0032-3888    

DOI:10.1002/pen.760100510

出版商:Society of Plastics Engineers, Inc.    

年代:1970

数据来源: WILEY

ISSN:0032-3888    

DOI:10.1002/pen.760100501

出版商:Society of Plastics Engineers, Inc.    

年代:1970

数据来源: WILEY