Phase morphology of as-molded and annealed blends of polyarylate/copolyester

The phase morphology of injection molded blends of polyarylate (PAR) and a copolyester (PCTG-5445) was studied by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The use of ultramicrotomy to prepare ? 50 nm thin section TEM specimens and solvent etching to dissolve the PAR phase revealed PCTG as the matrix phase in the as-molded state which crystallized into PCTG spherulites upon annealing. The most consistent morphological information vs. concentration of PCTG and the highest structural integrity of the PCTG spherulites was obtained from thin sections treated with a mixture of 75% methylene chloride as the solvent for the PAR and 25% 2-propanol as the nonreactive diluent. XRD results from the annealed PCTG/PAR blends show crystalline reflections of 0.59, 0.53, 0.46, 0.38, and 0.35 nm, which disappear into the amorphous background below 50% PCTG.     

Polysulphone and poly(phenylene sulphide) blends: 2. Mechanical behaviour

This paper reports the mechanical behaviour of injection moulded blends of polysulphone (PSF) and poly(phenylene sulphide) (PPS). The blends prepared by melt-extrusion and subsequent injection moulding are phase separated. Depending on moulding conditions, thermal history, and composition, tensile behaviour ranged from brittle to ductile, with or without cold drawing. Cold drawing was observed in compositions as-moulded with up to 50% by weight PPS. Upon annealing for 2h at 160°C, ductile failure was maintained for blends containing up to 35% by weight PPS. All other compositions failed in brittle fashion. Flexural strength and modulus, before and after annealing, exhibited negative deviation from the rule of mixtures. All the blends were found to be notch sensitive.     

An apparent double glass transition of polyphenylene sulfide in blends with polyarylate

Summary Injection molded blends of polyphenylene sulfide (PPS) and polyarylate (PAR) are phase separated as evidenced by transmission electron microscopy (TEM) micrographs and the existence of glass transition temperatures (T_g's) near 100 °C (PPS) and 190 °C (PAR). Upon annealing, blends that contain 15% to 40% by weight PPS exhibited unusual double glass transition temperatures (aside from PAR's T_g at 190 °C) at ca. 88 °C and 110 °C. These transitions coincide, respectively, with the T_g's of amorphous and crystalline PPS homopolymer. PPS crystallinity and average domain size distribution were found to be larger in the skin region than in the core region. It is believed that the double T_g's are brought about by different PPS domains with two types of amorphous material.     

PA6对聚苯硫醚多峰熔融行为的影响

用差示扫描量热法（DSC）研究了聚苯硫醚（PPS）/聚酰胺（PA）6共混物熔融多峰行为，PPS及其共混物均出现熔融多峰现象。但共混物呈现更加复杂的熔融行为，虽然退火结晶温度，时间和DSC扫描速率不同，但共混物中PPS的低温熔融峰温明显地比纯PPS的高，认为PA6与PPS间的相互作用促使PPS无定形态的退火结晶完善性提高。熔融多峰现象用重组机理来解释。     

Phase morphology and mechanical properties of blends of poly(p-phenylene sulfide) and polyamides

An experimental study of the blending, thermal transitions, phase morphology, and mechanical properties of poly(p-phenylene sulfide) (PPS)/polyamide blends is presented. Nylon-6, rubber modified nylon-6, nylon-66, nylon-11, nylon-12, and two partially aromatic amorphous polyamides were included in the study. Generally, blends of PPS with aromatic amorphous polyamides exhibit better mechanical properties than those with aliphatic polyamides. The blends with nylon-12 exhibit the best characteristics among the aliphatic polyamides.     

Tensile fracture morphology of polysulfone-poly(phenylene sulfide) blends

Summary Melt-extruded and subsequently injection molded polysulfone (PSF) and poly(phenylene sulfide) (PPS) blends exhibit very good tensile properties, at least up to 30–50% by weight of PPS. The tensile strength at the lower PPS contents shows additive effect or slightly better and materials fail in ductile mode. Tensile fracture surfaces were investigated using scanning electron microscopy (SEM). The 20% PPS blend shows no apparent voids between phases with some pull-out or elongation of the dispersed phase. At 35% PPS, phase boundaries were not clear and very rough surface profiles were observed. Blends with high PPS content (>50%) usually fail in the brittle mode. The fracture morphology of systems failing with a brittle mode revealed an interfacial debonding phenomenon.     

Izod impact fracture morphology of rubber-toughened polysulfone and poly(phenylene sulfide) blends

Blends of polysulfone (PSF) and poly-phenylene sulfide (PPS) exhibit ductile behavior, below 35% by weight PPS, under tensile loading conditions. However, the blends are notch sensitive to Izod impact. The use of a core-shell type rubber-modifier effectively toughens the blends. Notched Izod impact strength rises, from ～ 50 J/m to about 900 j/m, by increasing rubber content from 0% to 10–15%. It remains constant at a rubber content > 10–15%. Scanning electron microscopy (SEM) is used to study the morphology of the fracture surfaces. At low modifier content (5%), smooth or mesa-like fracture surfaces are observed. Voids and interfacial debonding are revealed. With a higher concentration of toughening agent (> 10%), some crazing is evidence but not consistent. However, matrix yielding and extensive plastic flow of the PSF/PPS matrix are seen throughout, with a higher level of rubber modifier.     

Compatibility and properties of alternating ethylene-tetrafluoroethylene copolymer and poly(methyl methacrylate) blends

Blends of an alternating ethylene-tetrafluorethylene copolymer (ETFE) and poly(methyl methacrylate) (PMMA) were prepared by melt mixing in a mixer. Compatibility, thermal behaviour and morphology of the blends of various compositions were investigated by using dynamic mechanical analysis (d.m.a.), Fourier transform infra-red spectroscopy (FTi.r.), solid-state nuclear magnetic resonance (n.m.r.) spectroscopy, differential scanning calorimetry (d.s.c.) and wide-angle X-ray diffraction. D.m.a. and d.s.c. results show that the glass transition temperature (T_g) of the ETFE in the blends increases as the PMMA content increases and the T_g of the PMMA moves to low temperatures when the ETFE content increases. In addition, d.s.c. results indicate an additional T_g, which is located between the T_g of PMMA and that of ETFE. The presence of this additional T_g suggests the existence of one semicrystalline phase and two amorphous phases—an ETFE/PMMA phase and a PMMA-rich phase. D.s.c. results also indicate that the melting temperature of ETFE decreases while the crystallinity of ETFE increases slightly as the PMMA content increases. FTi.r. results show that the absorption peak of the carbonyl group of the PMMA in the blends stays almost at the same position as in the pure component. Solid-state n.m.r. results reveal that the changes in chemical shift of the carbonyl group of PMMA in the blends are less than 0.5 ppm. These results confirm that only weak interactions exist between ETFE and PMMA. X-ray diffraction results reveal that no new crystal forms appear in the blends. © 1997 Elsevier Science Ltd.     

合成工艺对氮化硼纳米管显微结构和性能的影响

采用无定型B粉为原料,在催化剂Fe2O3和CaO辅助作用下,控制反应气氛氨气的流量(150~200 mL/min),在1200℃下于真空管式炉中保温4 h,制备氮化硼纳米管(BNNTs)。采用透射电子显微镜(TEM)、X射线衍射(XRD)和傅里叶转换红外光谱分析(FTIR)等手段对产物的结构和形貌进行了表征,结果表明:所得产物为竹节状氮化硼纳米管(BNNTs),其晶体结构为六方氮化硼,外径约为35~100 nm,长度为数微米至数十微米。     

Morphology,nonisothermal crystallization behavior,and kinetics of poly(phenylene sulfide)/polycarbonate blend

The morphology and nonisothermal crystallization behavior of blends made of poly(phenylene sulfide) (PPS), with a amorphous polycarbonate (PC) were studied. The blend is found to be partially miscible by the dynamic mechanical thermal analysis (DMTA) and melt rheological measurements. The nonisothermal crystallization behavior of blend was studied by differential scanning calorimetry (DSC). The results show clearly that the crystallization temperatures of PPS component in the blend decrease with increasing of PC contents. The crystallization kinetics was then analyzed by Avrami, Jeziorny, and Ozawa methods. It can be concluded that the addition of PC decreases the PPS overall crystallization rate because of the higher viscosity of PC and/or partial miscibility of blend, despite of small heterogeneous nucleation effect by the PC phase and/or phase interface. The results of the activation energy obtained by Kissinger method further confirm that the amorphous PC in the partial miscible PPS/PC blend may act as a crystallization inhibitor of PPS. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

注塑级PPES/PPS共混合金热性能及结晶性能的研究

通过熔融挤出、注塑成型的方法制备了配比不同的含二氮杂萘酮结构的聚芳醚砜(PPES)和聚苯硫醚(PPS）的共混物，对材料的热性能及结晶性能进行了研究。热失重研究表明，在所组成范围内PPS的加入并未降低共混物的热性能，但使共混物的热变形温度有所降低；PPES的加入使PPS的结晶受到阻碍，当PPES质量分数达80％时，PPS产生了晶格缺陷，从而不能形成完善的球晶，退火过程有利于提高共混物的热变形温度，使PPS形成更完善的球晶。     

Crystallization of an amorphous silicon nitride powder produced in a radiofrequency thermal plasma

Crystallization behavior of an amorphous silicon nitride powder produced in an RF thermal plasma by the vapor-phase reaction of silicon tetrachloride and ammonia has been investigated. Effects of annealing conditions such as temperature and duration of heat treatment on the properties of powders were studied. Changes in the chemical and phase compositions, as well as in the morphology of powders were measured and interpreted. Annealing of the amorphous silicon nitride powder at 1450°C for 120 min resulted in a powder of about 80% crystalline phase content with an /β ratio of about 6.5. ©     

Stabilization and control of phase morphology of PA/SAN blends via incorporation of exfoliated clay

The effect of nanoclay on phase morphology development of polyamide/styrene-acrylonitrile (PA/SAN) blends has been investigated. PA/SAN blends of various compositions, with and without the presence of exfoliated nanoclay in the PA phase, were prepared and the morphology of these blends was examined. Efforts have also included the study of morphology stability of these blends and the nanoclay effect on morphology stability of PA/SAN. The results suggest that at compositions where PA remains as the matrix domain, the nanoclay can be effective on reducing dispersed domain size to less than half the original size and furthermore improving the morphology stability of PA/SAN blends upon annealing by preventing coalescence of SAN domain. Implication of the present finding for effective preparation of stable incompatible blends is discussed.     

PPS/recycled PEEK/ carbon nanotube composites: Structure,properties and compatibility

Blends of poly(phenylene sulfide) (PPS) and recycled poly(ether ether ketone) (r‐PEEK) were prepared using a twin‐screw extruder. The carbon nanotube (CNT) added to the blends not only improved the compatibility of the two polymers, but also affected the morphology of the immiscible PPS/r‐PEEK blends. R‐PEEK always forms the dispersed phase and PPS the continuous phase in such blends. In the composite, CNT particles were observed in the PPS phase, mostly distributes in the interface between PPS and PEEK. The results show that r‐PEEK improves the impact and tensile strength of PPS, but does not provide nucleation effect on PPS. However, CNT improved the flexural modulus of PPS/r‐PEEK blends and promoted the crystallization of r‐PEEK rather than that of PPS. The prepared PPS/r‐PEEK blends provided larger electrical conductivity than neat polymers. Adding 20 wt % CNT to blend resulted in composite with the minimum volume resistivity, a reduction of four orders of magnitude, compared with that of the neat blend. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42497.     

Multiple melting behavior of polyphenylene sulfide blends with polyamide 6

Although there are many studies on the multiple melting behavior of polyphenylene sulfide (PPS) homopolymer, similar investigations on PPS component in PPS blends with thermoplastics are relatively rare. In the present paper, the multiple melting behavior of PPS blends with polyamide 6 (PA6) have been investigated by differential scanning calorimetry (DSC). The double melting peaks are also observed for PPS in the blends. Although the annealing temperature and time as well as the heating rate of DSC scanning are different, the lower melting peak temperature of PPS in the blend is higher than that of pure PPS and the higher melting peak temperature is lower than that of pure PPS. It is suggested that PA6 can accelerate the cold‐crystallization of amorphous PPS due to the possible presence of interfacial interaction between the component polymers to induce the heterogeneous nucleation, and increase the perfection of PPS crystals. The multiple melting behavior of PPS in the blends are explained by recrystallization. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1579–1585, 2000     

Phase behavior, morphology and interfacial structure in thermoset/thermoplastic elastomer blends of poly(propylene glycol)-type epoxy resin and polystyrene–b-polybutadiene

Thermoset/thermoplastic elastomer (TPE) blends of poly(propylene glycol) (PPG)-type epoxy resin (ER) and a diblock copolymer, polystyrene–b-polybutadiene (SB, with 30% styrene content), were prepared using 4,4′-diaminodiphenylmethane (DDM) as curing agent. The miscibility and thermal transition behavior of DDM-cured ER/SB blends were investigated by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The existence of three separate glass transitions, which are independent of the blend composition, indicates that SB is immiscible with DDM-cured ER. Neither the PS block nor the PB block exhibits miscibility with the cured ER. There exist three phases in the blends: a PS microphase, an ER-rich phase and a PB microphase. The phase structure and morphology of the ER/SB blends were studied using both scanning and transmission electron microscopy (SEM and TEM); a variety of morphologies were observed, depending on the blend composition. For the blends with 5 and 10 wt% SB, SB domains with irregular shapes and broadly distributed sizes are dispersed in a continuous cured ER matrix. For the blends with 20–60 wt% SB, interpenetrating bicontinuous phase structures are observed. For the blends with 70 wt% and more SB, a dispersion of cured ER particles in the SB matrix is obtained. The TEM observation showed that the two phases in the blends exhibit a good interfacial adhesion. The interfacial layer between the ER and SB phases varies from 100 to 300 nm for the blend with 20 wt% SB content, SB micelles are formed surrounding the SB domains in the ER matrix. Small-angle X-ray scattering (SAXS) experiments reveal that the SB diblock polymer still exhibits a lamellar microphase structure within the SB phase and the long spacing of lamellae nearly does not change in the blends. The SB diblock copolymer is microphase separated in the macroscopically phase separated ER/SB blends.     

Evaluation of olefinic block copolymer blends with amorphous polyolefins—effect of different unsaturated and saturated hydrocarbon tackifier resins on blend miscibility

Blends of ethylene–octene based olefinic block copolymer (OBC) with two amorphous polyolefin (APO) polymers [atactic propylene homopolymer (PP) and ethylene–propylene copolymer (PE–PP)] were evaluated at three different ratios. Dynamic mechanical analysis (DMA) and transmission electron microscopy (TEM) evaluations were performed to determine the blend miscibility characteristics. Viscoelastic properties of both OBC blends with PP polymer, and OBC blends with PE–PP copolymer showed incompatibility. Analysis revealed that both blends formed two phase morphologies. The effect of three unsaturated aliphatic hydrocarbon resins with varying aromatic content and two saturated hydrocarbon resins with different chemistries were evaluated as compatibilizing agent for OBC/PP and OBC/PE–PP blends. A 1 : 1 polymer blend ratio of OBC/PP and OBC/PE–PP was selected to better understand the influence of resin addition at three different levels 20, 30, and 40 wt %. The fully aliphatic unsaturated resin seems to improve the miscibility of the OBC/PP blends at higher resin addition levels, but reduced the miscibility as the aromatic content of the resin increases. However, OBC/PE–PP blends showed improved miscibility with increasing aromatic content. A ternary phase morphology was particularly observed for both OBC/PP and OBC/PE–PP blends with highly aromatic (14%) unsaturated hydrocarbon resin, in which OBC formed the continuous phase, and PP, PE–PP, and unsaturated hydrocarbon resins formed the dispersed phase. Interestingly, we did not observe much difference in miscibility characteristics between the two saturated resin chemistries in both blend systems (OBC/PP and OBC/PE–PP). The Harkins spreading coefficient concept was used to better understand the ternary blend dispersed phase morphology. Spreading coefficients indicate that the free hydrocarbon resins (both unsaturated and saturated) were encapsulated by the amorphous PP or amorphous PE–PP polymer in the dispersed phase for the respective blend compositions. Overall OBC–PP and OBC/PE–PP blends showed better miscibility characteristics with both saturated aliphatic hydrocarbon resins, irrespective of the difference in resin chemistries. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2624–2644, 2013     

Thermal characterization and morphological study of polyphenylene sulfide–polycarbonate blends

The thermal behavior and phase morphology of binary blends of poly(phenylene sulfide) (PPS) with polycarbonate (PC) have been investigated. Differential scanning calorimetry and dynamic mechanical thermal analysis indicate the blends are immiscible, but the glass transition temperature of PC in the blends was found to be decreased due to the degradation of the PC. The PC degradation was investigated by measuring the molecular weight of PC extracted from the blends. Rheological properties of the blends were also studied using a rheodynamic spectrometer. An inversion of the phase morphology was observed from the scanning electron microscopy and dynamic mechanical thermal analysis. The increase of crystallinity of the PPS in the blends was found from a DSC study.     

Thermally crosslinkable poly(phenylene sulfide)/poly(ether sulfone)/polymerization of monomer reactant–polyimide blends

The effects of thermally crosslinkable polymerization of monomer reactant–polyimide (POI) on the miscibility, morphology, and crystallization of partially miscible poly(ether sulfone) (PES)/poly(phenylene sulfide) (PPS) blends were investigated with differential scanning calorimetry and scanning electron microscopy. The addition of POI led to a significant reduction in the size of PPS particles, and the interfacial tension between PPS and crosslinked POI was smaller than that between PES and crosslinked POI. During melt blending, crosslinking and grafting reactions of POI with PES and PPS homopolymers were detected; however, the reaction activity of POI with PPS was much higher than that with PES. The crosslinking and grafting reactions were developed further when blends were annealed at higher temperatures. Moreover, POI was an effective nucleation agent of the crystallization of PPS, but crosslinking and grafting hindered the crystallization of PPS. The final effect of POI on the crystallinity of the PPS phase was determined by competition between the two contradictory factors. The crosslinking and grafting reactions between the two components was controlled by the dosage of POI in the blends, the premixing sequence of POI with the two components, the annealing time, and the temperature. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2906–2914, 2002; DOI 10.1002/app.10287     

Rheology of blends of a thermotropic liquid crystalline polymer with polyphenylene sulfide

Blends of thermotropic liquid crystalline polymer (LCP) and polyphenylene sulfide (PPS) were studied over the entire composition range using Rheometrics Stress Rheometer, capillary rheometer, and differential scanning calorimeter. There is no molecular scale mixing or chemical reaction between the components, as evidenced by melting and crystallization points in the PPS phase. From the strain scaling transients test at low‐rate, LCP and the blends require approximately 60 strain units to obtain steady stale shearing results. The large recoveries in the strain recovery test, magnitude 3 to 3.3 strain unit, are likely the results of texture present in LCPs. With increasing PPS content in LCP/PPS blends, the total recovery declines. Scaling of the transient strain rate remains, but the magnitude of the transients is reduced. At low‐rate, when the LCP is added to the PPS, the pure melts have similar visosity: 500 Pa · s for LCP and 600 Pa · s for PPS, but the viscosity of the blends goes through a maximum with concentration that is nearly three times the viscosity of the individual melts. At high‐rate, a significant depression of the viscosity is observed in the PPS‐rich compositions and this may be due to the fibrous structure of the LCP at high shear rates.