摘要:

AbstractPoly(elhylene terephthalate) samples were isothermally crystallized from the melt on a differential scanning calorimeter. Subsequent fusion showed three endotherms under many crystallization conditions. These three peaks are attributed to melting of crystallites formed daring primary and secondary crystallization processes and to fusion of crystals formed during recrystallizatlon during the melting scan.

ISSN:0032-3888    

DOI:10.1002/pen.760280202

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractInvestigations of instability of phase morphology of blends of nylons with polyethylenes and polystyrenes and the effects of “compatibilizing” additives or “agents” are described. Annealing coarsens the phase morphology of blends of nylons with polyethylenes and polystyrenes. Phase growth is observed for various periods of annealing time. The addition of compatibilizing agents, specifically maleic anhydride grafted polyolefins to polyethylene‐nylon blends and syrene‐maleic anhydride copolymers to polystyrene‐nylon blends, stabilize the phase dimensions. Styene‐maleic anhydride copolymer is found more effective than styrene acrylonitrile copolymer as a compatibilizing agent. The mechanisms of this behavior are criti

ISSN:0032-3888    

DOI:10.1002/pen.760280203

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractA method to obtain the tenacity and Young's modulus of nonwoven webs without direct measurement of web thickness is proposed. This has been tested with several series of samples with different basis weight. It was found that these properties were nearly Independent of the sample gage length, and both tenacity and modulus generally decreased with increase in the die temperature, the air pressure at the die, or the die to collector distance [DCD]. The web stiffness as measured by bending rigidity followed similar trends. The elongation Lo break also decreased as die temperature and air pressure at The die increased, but it increased with increasing DCD. The average filament diameter in the web decreased with increasing die temperature or air pressure at the die. The single filament strength was measured and compared with strength properties of web and of high‐speed melt spun filament prepared from the same resins. The strength of single filaments in the web lie in between those of the web and high‐speed spun filaments. The mechanical properties of melt blown web were interpreted in terms of the changes in Fiber diameter, the level of interfilament bonding, the molecular orientation developed in the filament, the diameter uniformity along the individual filaments in the web, and the presence of voids in the filam

ISSN:0032-3888    

DOI:10.1002/pen.760280204

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractRheological data have been collected in isothermal elongational flow for three different types of blends, made from one low density polyethylene and three linear low density samples. In addition to the transient curves, elongation at break data are also reported. The influence of the composition and of the molecular weight of the linear low density polyethylene is discussed.

ISSN:0032-3888    

DOI:10.1002/pen.760280205

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractTransport of liquid cyclohexane through well characterised, initially glassy, crosslinked polystyrene slabs was Investigated at 20, 30, 40, and 50°C. The samples used were produced by bulk polymerization of styrene and divinyl benzene (DVB) at 90°C for 43 hr using benzoyl peroxide as an initiator. The samples tested had initial cross‐linking ratios, X, between 5 and 25 × 10−3mol DVB/mol styrene. The initial thickness of the samples tested varied from 0.25 mm to 1.80 mm, and the aspect ratio (length to thickness ratio) was maintained above 10;1 in order to analyze the results by one‐dimensional transport equations. Cyclohexane uptake was followed as a function of time along with dimensional changes in the thickness and area of the samples. The results of penetrant uptake as a function of time were analyzed using a simplified exponential expression and employing all the data points from the beginning of the experiment until the time of observation of the maximum in uptake. Good correlations were established between the penetrant uptake and the transport temperature. These results were interpreted in terms of competitive relaxational and diffusional me

ISSN:0032-3888    

DOI:10.1002/pen.760280206

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractThe morphology of polycarbonate (PC)‐poly(butylene terephthalate) (PBT) blends prepared by melt‐processing in an extruder or a Brabender Plastograph was studied by Transmission Electron Microscopy. Transesterification during blending was avoided by the use of di‐n‐octadecyl phosphite, an efficient transesterification inhibitor. Ruthenium tetraoxide was used to selectively stain the PC fraction. Observation of ultrathin sections revealed the biphasic nature of the blends and the partial compatibility of the polymers in the molten state. The most striking consequence of this Is the presence, of PBT crystalline lamellae growing inside the PC‐rich phase for samples annealed in the proper temperature range. A preliminary study of the morphology as a function of composition and thermal annealing was undertaken. The RuO4staining technique was also applied to the commercial blend Xenoy CL 100 from General Electric, which was shown to contain an MBS impact modifier (a methylmethacrylate butadiene‐styrene copolymer) exclusively located In the PC

ISSN:0032-3888    

DOI:10.1002/pen.760280207

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractA computer simulation model for the latent skin growth inside a hollow fiber polymeric membrane Is developed. The evaporation step is studied using a solvent evaporation Law and a concentration‐dependent diffusion coefficient, both derived from data. The solvent concentration profiles inside the fiber are obtained as a function of the evaporation time for different sets of the parameters governing the internal diffusion and the surface evaporation of the solvent. The computer model enables estimation of the role of the parameters in the growth of the asymmetric latent ski

ISSN:0032-3888    

DOI:10.1002/pen.760280208

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

ISSN:0032-3888    

DOI:10.1002/pen.760280201

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY