摘要:

AbstractIn a cooperative testing of polymer blends of polycarbonate (PC) and linear low‐density polyethylene (LLDPE), 17 laboratories from six countries contributed measurements of differential scanning calorimetry (DSC) or differential thermal analysis (DTA) and of thermogravimetric analysis (TGA). This work is part of the activity of the VAMAS* Technical Working Party–Polymer Blends (TWP–PB), which provided the samples and coordinated the tests. Thermal analysis proved to be a, rapid means of assessing the miscibility of polymers using small samples. The system PC/LLDPE investigated in this test is found immiscible. The results of this cooperative test are a basis to elaborate a standard procedure for the characterization of polymer b

ISSN:0032-3888    

DOI:10.1002/pen.760281702

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractThe phase equilibrium of the ternary system poly (vinyl chloride) (PVC)/styrene‐acrylonitrile copolymer (77/23) (SAN)/poly (methyl methacrylate) (PMMA) was investigated using a combination of turbidity, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) measurements. Both turbidity and DSC were used to determine room temperature ternary phase diagrams. The results are basically similar, but the formulation based on the DSC results and the presumed phase model would seem more reliable since it is possible that immiscible blends may well have different phases with similar refractive indice

ISSN:0032-3888    

DOI:10.1002/pen.760281703

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractWe present a basic study of the thermal, dielectric, Theological, and mechanical properties of hydroxybenzoic acid‐ethylene terephthalate copolymers (PHB‐PET). It is argued that they have two‐phase structures, one rich in ethylene terephthalate (PET) and one rich in hydroxybenzoic acid (PHB). Polystyrene (PS) is immiscible in 60% PHB‐PET (60‐PHB‐PET) blends. Polycarbonate (PC) is partially miscible with the high PET phase of 60‐PHB‐PET. PET seems completely miscible with this high PET phase. Shear viscosity measurements on blends indicate that 60‐PHB‐PET gives rise to large reductions of viscosity. Extrudates and melt‐spun fibers have been prepared. The phase morphologies of low PHB‐PET blends as determined by scanning electron microscopy indicate ellipsoids or long fibrils of the, 60‐PHB‐PET in PS or PC matrices. High extrusion rates and melt spinning produce fibrillar structures. The mechanical properties of films, extrudates, and melt‐spun fibers were studied. Blends with 10% 60‐PHB‐PET exhibited significant increases in You

ISSN:0032-3888    

DOI:10.1002/pen.760281704

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractRheological and spiral mold flow measurements were made on blends of a chlorinated poly (vinyl chloride) (CPVC) compound and a thermotropic liquid crystalline copolyester of p‐hydroxybenzoic acid/poly (ethylene terephthalate) (60/40), hereafter referred to as LCC, at 210°C. Several interesting flow phenomena have been observed. While the shape of the flow curve (i.e.,G′ vs. ω;G″ vs. ω) of LCC is solidlike, those of the blends are pseudoplastic. The dynamic viscosity of the blends increases as the concentration of LCC increases. However, the shear viscosity of the blends is reduced with LCC and may be described using the relationship of additivity of fluidity. Although the melt elasticity of the blends is increased with the concentration of LCC, the extrudate swell of the blends after extrusion from a capillary is decreased. This phenomenon, however, is complicated. A Theological analysis based on an idealized runner system is used to describe the spiral flow length as a function of the Theological properties of the molten polymers and also the operating conditions. The relative improvement of the spiral flow length of the CPVC compound due to blending with LCC could be correlated with the power‐law fluid model at high s

ISSN:0032-3888    

DOI:10.1002/pen.760281705

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractBlends of bisphenol‐Apolycarbonate (PC) with poly‐ (styrene‐co‐acrylonitrile) (SAN) and poly (acrylonitrile‐butadiene‐styrene) (ABS) prepared by screw extrusion and solution‐casting were investigated by differential scanning calorimetry and scanning electron microscopy. From the measured glass‐transition temperatures (Tg) and specific heat increments (ΔCp) at theTg, SAN appears to dissolve more in the PC‐rich phase than does PC in the SAN‐rich phase. Also, the decrease ofTg(PC) in PC/ABS blends is larger than in the PC/SAN blends. From theTgbehavior and the electron microscopy study, it is suggested that the compatibility increases more in the SAN‐rich compositions than in the PC‐rich compositions of the blends. In the study of extrudate swell of the PC/SAN blends and the PC/ABS blends, the maximum level of extrudate swell is reached at 0.5 weight fraction of PC for both blend systems. The Flory‐Huggins polymer‐polymer interaction parameter (χ12) between PC and SAN was calculated and found to be 0.034 ± 0.004. A similar value of χ for PC and SAN w

ISSN:0032-3888    

DOI:10.1002/pen.760281706

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractMelt‐mixed blends of polycarbonate/phenoxy were obtained before and after Interchange reactions by controlling the processing time. The dynamic mechanical analysis of the physical and reacted blends confirmed the immiscibility of the pair and the displacement of the glass‐transition temperatures of the mixtures; this displacement was seen more clearly in the reacted mixtures, and at phenoxy‐rich contents, even a single phase can appear. The exchange reactions resulted in a mechanical behavior that showed both a higher modulus and greater tensile strength in the reacted blends. The ductility was close to linearity for the physical blends and probably would be improved in the reacted mixture with a lower processing

ISSN:0032-3888    

DOI:10.1002/pen.760281707

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractBlends of linear low‐density polyethylene (LLDPE) and a 50:50 copolymer of octadecene and maleic anhydride (C18‐MAH) were characterized by calorimetry, dynamic mechanical testing, and rheometry. In the solid state, the blends are essentially immiscible. No evidence was obtained for cocrystallization of the LLDPE with the paraf‐finic side‐chains of the C18‐MAH. Interactions between the blend components were observed in three ways. First, presence of the C18‐MAH in the LLDPE melt increases the nucleation rate for LLDPE crystallization. Second, side‐chain crystallization in a portion of the C18‐MAH component equivalent to approximately 15% of the total blend is apparently suppressed in the blends. Third, although the mechanical loss of the blends is essentially a sum of the pure components, the β relaxation of the LLDPE is absent in blends containing more than 20% C18‐MAH. The blends are also immiscible in the melt. The steady and dynamic shear rheology is dominated by the immiscibility and mismatch in viscosity, η, between the two polymers. A linear dependence on blend composition was found for log η in dynamic (small strain) tests. Nonlinear behavior with positive and negative deviations from linearity was found for log η in steady shear

ISSN:0032-3888    

DOI:10.1002/pen.760281708

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

ISSN:0032-3888    

DOI:10.1002/pen.760281701

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY