Mechanical and dielectric breakdown properties of PBT/TPE,PBT/PBT/PET,and PBT/antioxidant blends

To improve the thermal aging flexibility of poly(butylene terephthalate) (PBT), PBT was melt‐blended with three type thermoplastic elastomer [poly ether‐ester type (TPE1), polyester‐ester type (TPE2), and poly(buthylene 2,6‐naphthalate)/poly(tetramethylene glycol) block copolymer type (TPE3)], PBT/poly(ethylene terephthalate), (PET) alloy (Alloy), and phosphate type antioxidant (T1). The content of the three type TPEs and Alloy was fixed at 20 parts per 100 g of PBT. The morphology and thermal behavior of these blends have been investigated with scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetry (TG). In the case of PBT/Alloy‐20 and PBT/TPE3–20 blends show clean fractured surface, whereas for PBT/TPE1–20 and PBT/TPE2–20 blends, the elongated pieces or fiber can be seen abundantly which indicates a good compatibility. TG traces show a significant shift of the weight loss toward higher temperature for PBT/Alloy‐20, whereas PBT/TPE1–20, PBT/TPE2–20 and PBT/TPE3–20 blend decrease in thermal stability than PBT. To investigate the applicability for insulation material, the prepared blend samples were extruded an electric wire and flexibility and electric breakdown voltage (BDV) of wire after thermal aging were studied. For PBT/TPE1–20 and PBT/TPE2–20 blends did not show any cracks after flexibility test at 130°C for 6 h and 225°C for 30 min. In contrast PBT, PBT/Alloy‐20, PBT/TPE3–20, and PBT/T1–1 showed a partial crack in the insulation after flexibility test at 130°C for 6 h although its good flexibility at 225°C for 30 min. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Melting,crystallization behaviors,and nonisothermal crystallization kinetics of PET/PTT/PBT ternary blends

The melting, crystallization behaviors, and nonisothermal crystallization kinetics of the ternary blends composed of poly(ethylene terephthalate), poly(trimethylene terephthalate) (PTT) and poly(buthylene terephthalate) (PBT) were studied with differential scanning calorimeter (DSC). PBT content in all ternary blends was settled invariably to be one‐third, which improved the melt‐crystallization temperature of the ternary blends. All of the blend compositions in amorphous state were miscible as evidenced by a single, composition‐dependent glass transition temperature (T_g) observed in DSC curves. DSC melting thermograms of different blends showed different multiple melting and crystallization peaks because of their various polymer contents. During melt‐crystallization process, three components in blends crystallized simultaneously to form mixed crystals or separated crystals depending upon their content ratio. The Avrami equation modified by Jeziorny and the Ozawa theory were employed to describe the nonisothermal crystallization process of two selected ternary blends. The results spoke that the Avrami equation was successful in describing the nonisothermal crystallization process of the ternary blends. The values of the t_1/2 and the parameters Z_c showed that the crystallization rate of the ternary blends with more poly(ethylene terephthalate) content was faster than that with the lesser one at a given cooling rate. The crystal morphology of the five ternary blends investigated by polarized optical microscopy (POM) showed different size and distortional Maltese crosses or light spots when the PTT or poly(ethylene terephthalate) component varied, suggesting that the more the PTT content, the larger crystallites formed in ternary blends. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Study on in situ reinforcing and toughening of a semiflexible thermotropic copolyesteramide in PBT/PA66 blends

Ternary in situ composites based on poly(butylene terephthalate) (PBT), polyamide 66 (PA66), and semixflexible liquid crystalline polymer (LCP) were systematically investigated. The LCP used was an ABA30/PET liquid crystalline copolyesteramide based on 30 mol % of p‐aminobenzoic acid (ABA) and 70 mol % of poly(ethylene terephthalate) (PET). The specimens for thermal and rheological measurements were prepared by batch mixing, while samples for mechanical tests were prepared by injection molding. The results showed that the melting temperatures of the PBT and PA66 phases tend to decrease with increasing LCP addition. They also shifted toward each other due to the compatibilization of the LCP. The torque measurements showed that the ternary blends exhibited an apparent maximum near 2.5–5 wt % LCP. Thereafter, the viscosity of the blends decreased dramatically at higher LCP concentrations. Furthermore, the torque curves versus the PA66 composition showed that the binary PBT/PA66 blends can be classified as negative deviation blends (NDBs). The PBT/PA66/LCP blends containing up to 15 wt % LCP were termed as positive deviation blends (PDBs), while the blends with the LCP ≥25 wt % exhibited an NDB behavior. Finally, the tensile tests showed that the stiffness and tensile strength of ternary in situ composites were generally improved with increasing LCP content. The impact strength of ternary composites initially increased by the LCP addition, then deteriorated when the LCP content was higher than 10 wt %. The correlation between the mechanical properties and morphology of the blends is discussed. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1975–1988, 2000     

PET/聚酰胺类共混体系相容性的研究

将聚对苯二甲酸乙二醇酯(PET)分别与聚酰胺类(PA1010、PA6和PA66)熔融共混,通过热力学分析、示差扫描量热法、扫描电镜和红外光谱等手段,对PET/PA类共混体系进行了研究.热力学分析结果与实验结果不同,表明热力学分析不适用于PET/PA共混体系;DSC分析结果表明:不同的PET/PA共混体系对PET相玻璃化温度向低温区移动程度有影响;SEM分析表明:PET/PA共混体系断面形态不同,相容性关系为PET/PA66>PET/PA6>PET/PA1010;红外光谱分析表明:共混体系中PET的羟基和PA分子的-NH-之间产生了氢键,导致PET的C=0拉伸震动吸收峰移向低波数.     

Mechanical and thermal properties of copoly(styrene/acrylonitrile) compatibilised Nylon–thermoplastic elastomer blends

Abstract

The effects of blend compositions on the mechanical and thermal properties of polymer blends containing Nylon 66 and a thermoplastic elastomer (TPE), Santoprene^®, have been studied. A 5% styrene/acrylonitrile copolymer was added to neat Nylon, TPE, and their blends. The blends were injection moulded and the tensile and impact properties were investigated. The morphology and thermal properties of the blends were observed using scanning electron microscopy and differential scanning calorimetry.

The presence of double melting temperatures showed that the Nylon 66 and TPE are immiscible. However, blending produced a modification of mechanical and thermal properties. At TPE/Nylon ratios above 50 : 50 the tensile properties of TPE improved. In addition the impact properties of Nylon improved above the 50 : 50 ratio, i.e. in the TPE rich region. Both the melting temperature and crystallinity were depressed in the region of 50 : 50 blend composition. The presence of two phases, which is evidence of immiscibility of the blends, was confirmed by scanning electron microscopy.     

In situ fibrillar reinforced PET/PA‐6/PA‐66 blend

Ternary fibrillar reinforced blends are obtained by melt‐blending of poly(ethylene terephthalate) (PET), polyamide 6 (PA‐6) and polyamide 66 (PA‐66) (20/60/20 by weight) in the presence of a catalyst, followed by cold drawing of the extruded bristles to a draw ratio of about 3.4 and additional annealing of the drawn blend at 220 or 240°C for 4 or 8 h. The blend samples are studied by DSC, X‐ray diffraction, SEM, and static and dynamic mechanical testing (DMA). SEM and DMA show that PA‐6 and PA‐66 form a homogeneous, continuous matrix in which PET regions are dispersed. X‐ray and DSC measurements of the drawn and annealed at 220°C samples suggest mixed crystallization (solid solubility) of PA‐6 and PA‐66, and cooperative crystallization of PET with the two polyamides. After annealing at 240°C (above the melting point of PA‐6 and below that of PET), the polyamide matrix becomes partially disoriented, while the oriented, fibrillar PET is preserved and plays the role of a reinforcing element. The DSC results for the same samples suggest in situ generation of an additional amount of copolymer. This additional copolymerization, together with that generated during blend mixing in the extruder, improves the compatibility of the blend components (mostly at the PET‐polyamide interface) and alters the chemical composition of the blend.     

Random orientation of in situ composites based on liquid‐crystalline polymers by compression moulding

In this study, randomly oriented in situ composites based on liquid‐crystalline polymers (LCPs) were prepared by thermal compression moulding. The LCP employed was a semi‐flexible liquid‐crystalline copolyesteramide with 30 mol% of p‐aminobenzoic acid (ABA) and 70 mol% of poly(ethylene terephthalate) (PET). The matrices were poly(butylene terephthalate) (PBT) and polyamide 66 (PA66). The rheological properties, compatibility and morphological structures of these in situ composites were investigated. The results showed that PA66‐LCP and PBT–LCP component pairs of the composites are miscible in the molten state, but partially compatible in the solid state. The ratios of viscosity, λ₁ = η_LCP/η_PA66 and λ₂ = η_LCP/η_PBT, are all greater than 1.0. However, the melt viscosity of the LCP/PBT and LCP/PA66 blend is much lower than that of PBT and PA66, and it decreases markedly with increasing LCP content. When the LCP/PA66 or LCP/PBT blends are compression moulded, the LCP/PA66 or LCP/PBT melts and flows easily due to their low viscosity, and the LCP phases in the melts deform easily along the flow directions, which are random. It leads to uniformly dispersed LCP micro‐fibres randomly orientation in the thermoplastic matrix due to the compatibility between the blending components. © 2003 Society of Chemical Industry     

Non-isothermal crystallization kinetic of recycled PET and its blends with PBT modified with epoxy-based multifunctional chain extender

A fundamental understanding of crystallization behavior is essential for the processing of both virgin and recycled polymers. This research delves into the crystallization characteristics and non-isothermal crystallization kinetics of recycled polyethylene terephthalate (rPET) and its blends with poly butylene terephthalate (PBT), which have been modified using epoxy-based multifunctional chain extenders (CE). The preparation of rPET/PBT blends involved a twin-screw extruder, with varying weight ratios and different CE concentrations. Differential scanning calorimetry was employed to perform crystallization analysis on the samples. The results underscore the profound impact of blend composition on the thermal characteristics of the system, with CE exerting only a marginal influence. The glass transition temperatures (T_g) of the two polymers were measured at 49 and 79°C. During blending, the T_g values demonstrated variations relative to the proportions but did not adhere to the Fox equation. Furthermore, PBT was found to enhance the crystallization tendencies of rPET, resulting in an increase in relative crystallinity from 11% to 36%. Notably, the crystallization rate of PBT at 0.40 min⁻¹ exceeded that of rPET at 0.36 min⁻¹. PBT minimally affected the crystallization rate constant of rPET-dominant blends, while rPET significantly reduced the crystallization rate in PBT-dominant blends.     

Morphology evolution of immiscible polymer blends as directed by nanoparticle self-agglomeration

This work aims to clarify the effect of nanoparticle self-agglomeration structure on the morphology of polymer blends. The morphology development of polystyrene (PS)/polyamide (PA6) blends with titanium dioxide (TiO₂) nanoparticles preferentially localized in the PA6 domains was investigated by means of electron microscopy observation, viscoelastic analysis and selective extraction tests. It was shown that the preferential dispersion of TiO₂ leads to a significant reduction of the PA6 continuity in the PS/PA6 blend. The size of the PA6 domain increases gradually with further increasing the nanoparticle loading whereas the co-continuity of the PS/PA6/TiO₂ mixture is destroyed by isothermal post-treatments. These experimental results are completely different from those in carbon black, nanoclay or nano-silica-filled immiscible polymer blends. To elucidate the progression to the uneven morphology change, the dynamic process of microfibril break-up and droplet coalescence in the molten PS/PA6/TiO₂ mixture was traced in real-time through optical microscopy. It was confirmed that the self-agglomerating pattern of the nanoparticle in the polymer melts plays a key role in directing the morphology evolution of the immiscible polymer blend: unlike the self-agglomeration of carbon black to form three-dimensionally continuous network structure, the TiO₂ nanoparticles tend to form separate clusters in the PA6 phase. This prevents PA6 droplets from fusing together to form a continuous network during the coalescence and producing larger PA6 domains at higher TiO₂ loads.     

Mechanical,chemical, thermal,and rheological properties of recycled PA6/ABS binary and PA6/PA66/ABS ternary blends

The effects of multiple injection molding cycles on the chemical and mechanical properties of PA6/ABS and PA6/PA66/ABS blends are investigated. The chemical structures of both PA6/ABS binary and PA6/PA66/ABS ternary blends do not alter after recycling process. For PA6/ABS binary blend, it is found that the tensile strength, strain at break, elastic modulus, impact strength, flexural strength, and modulus of recycled blend decrease by 6.49%, 15.19%, 21.00%, 9.41%, 7.09%, and 8.25%, respectively, while MFI increases by 23.59% as compared with the virgin blend. After five recycling process for PA6/PA66/ABS ternary blend, the tensile strength, strain at break, and impact strength of recycled blend decrease by 18.00%, 50.80%, and 87.27%, respectively. However, flexural strength and modulus of PA6/PA66/ABS blend increase slightly. For virgin PA6/PA66/ABS blend, MFI value was 7.7 g/10 min and with recycling this value showed an important increase to 31.56 g/10 min after five cycles. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40810.     

Polyethylene terephthalate/low density polyethylene/titanium dioxide blend nanocomposites: Morphology,crystallinity, rheology,and transport properties

Physical features of polyethylene terephthalate (PET)/low density polyethylene (LDPE) immiscible blends, rich in PET, with and without titanium dioxide (TiO₂) nanoparticles are studied. These materials are of industrial interest, because they can be obtained by recycling PET bottles containing TiO₂ with their corresponding polyethylene made caps. Their potential application in packaging is investigated. Droplet-matrix morphology is observed by scanning electron microscopy; coalescence occurs during compression molding. Transmission electron microscopy results show that TiO₂ nanoparticles are located at the interface between PET and LDPE, forming a physical barrier that favors development of smaller droplets. Thermal analysis results are compatible with the morphology of the blends and the location of the TiO₂ nanoparticles. Viscosity obtained by extrusion continuous flow and oscillatory flow measurements in the linear regime show that some of the blends have viscoplastic behavior. Permeability results reveal that 80PET/20LDPE/TiO₂ blend nanocomposite shows a balanced barrier character to both oxygen and water vapor. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46986.     

Morphology and properties of PET/PA‐6/SiO2 ternary composites

A kind of hydrophilic nano‐SiO₂ was applied to poly(ethylene terephthalate)/polyamide‐6 (PA‐6) blends. Melt‐blended composites were prepared at various component ratios and different nano‐SiO₂ levels. Mechanical, morphological, dynamic mechanical, and thermal tests were carried out to characterize the properties, morphology, and compatibilization of the composites. Increased impact strength, tensile strength, and modulus were observed by adding nano‐SiO₂ particles in the blends. The nano‐SiO₂ particles were found to be preferentially dispersed in PA‐6, resulting in an increase of glass transition temperature and crystallization of PA‐6. The mechanism of morphology and properties changes was discussed based on the selective dispersion of nano‐SiO₂ particles in the blends. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2288–2296, 2007     

Nonisothermal crystallization and melting behavior of β‐nucleated isotactic polypropylene and polyamide 66 blends

A highly novel nano‐CaCO₃ supported β‐nucleating agent was employed to prepare β‐nucleated isotactic polypropylene (iPP) blend with polyamide (PA) 66, β‐nucleated iPP/PA66 blend, as well as its compatibilized version with maleic anhydride grafted PP (PP‐g‐MA), maleic anhydride grafted polyethylene‐octene (POE‐g‐MA), and polyethylene‐vinyl acetate (EVA‐g‐MA), respectively. Nonisothermal crystallization behavior and melting characteristics of β‐nucleated iPP and its blends were investigated by differential scanning calorimeter and wide angle X‐ray diffraction. Experimental results indicated that the crystallization temperature (T) of PP shifts to high temperature in the non‐nucleated PP/PA66 blends because of the α‐nucleating effect of PA66. T of PP and the β‐crystal content (K_β) in β‐nucleated iPP/PA66 blends not only depended on the PA66 content, but also on the compatibilizer type. Addition of PP‐g‐MA and POE‐g‐MA into β‐nucleated iPP/PA66 blends increased the β‐crystal content; however, EVA‐g‐MA is not benefit for the formation of β‐crystal in the compatibilized β‐nucleated iPP/PA66 blend. It can be relative to the different interfacial interactions between PP and compatibilizers. The nonisothermal crystallization kinetics of PP in the blends was evaluated by Mo's method. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Isothermal crystallization and melting behaviors of nano TiO2‐modified polypropylene/polyamide 6 blends

Titanium dioxide (TiO₂) nanoparticles were functionalized with toluene‐2,4‐diisocyanate and then polypropylene/polyamide 6/(PP/PA6) blends containing functionalized‐TiO₂ were prepared using a twin screw extruder. Isothermal crystallization and melting behavior of the as‐prepared composites were investigated using differential scanning calorimetry and wide‐angle X‐ray diffraction. Isothermal crystallization analysis shows that the TiO₂ nanoparticles have two effects on PP/PA6 blends, i.e., it can favor the improvement of crystallization ability and decrease the crystallization rate of PP/PA6 blends. The improvement of crystallization ability is superior over decreasement of crystallization rate of PA6 chains caused by TiO₂, therefore PA6 in PP/PA6/TiO₂ nanocomposites have higher crystallization rate than that of PA6 in pure PP/PA6 blends, which indicated TiO₂ nanoparticles favored the crystallization of PA6. The TiO₂ nanoparticles show no effects on the equilibrium melting temperature (T) values of PP phase but decreases the T values of PA6 phase. In addition, the TiO₂ nanoparticles did not change the crystalline polymorph of PP/PA6 blends basically; however, favored the formation of β‐PP. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

液晶共聚酯酰胺对PET／PA66的原位增容,增强,增韧作用

研究了液晶共聚酯酰胺ＬＣ３０对聚树苯二甲酸乙二酯／聚酰胺６６共混物的原侠增容，增强，增韧作用。结果表明，ＬＣ３０有效地改善了ＰＥＴ／ＰＡ６６共混物的形态结构，对ＰＥＴ／ＰＡ６６共混物起到了明显的增容作用。     

聚苯醚接枝马来酸酐/聚酰胺66共混物的制备与性能

通过辐照法将马来酸酐(MAH)基团接枝到聚苯醚(PPE)上,制备了PPE-g-MAH,将其和聚酰胺(PA)66通过熔融共混挤出方法制备了PPE-g-MAH/PA66共混物。采用差示扫描量热、吸水性实验、维卡软化和热变形实验、拉伸和冲击性能测试及动态力学性能测试等对PPE-g-MAH/PA66共混物性能进行了研究。结果表明,与PPE/PA66共混物相比,PPE-g-MAH/PA66共混物的耐热性能、力学性能和吸水性能均得到改善;随PPE-g-MAH含量的增加,PPE-g-MAH/PA66共混物中PA66的熔融温度和玻璃化转变温度均向PPE方向移动,表明两者的相容性有所提升,且共混物的维卡软化温度、热变形温度、25℃之前的储能模量均升高,吸水率降低;当PPE-g-MAH含量较低时,共混物拉伸强度提升明显而冲击强度升幅较小,当PPE-g-MAH含量较高时,共混物冲击强度提升明显而拉伸强度基本不变。因此,可以根据实际的应用要求选择合适的PPE-g-MAH含量。     

Synthesis and properties of reactively compatibilized polyester and polyamide blends

The functionalization of poly(butylene terephthalate) (PBT) has been accomplished in a twin screw extruder by grafting maleic anhydride (MA) using a free radical polymerization technique. The resulting PBT‐g‐MA was successfully used as a compatibilizer for the binary blends of polyester (PBT) and polyamide (PA66). Enhanced mechanical properties were achieved for the blend containing a small amount (as low as 2.5 %) of PBT‐g‐MA compared to the binary blend of unmodified PBT with PA66. Loss and storage moduli for blends containing compatibilizer were higher than those of uncompatibilized blends or their respective polymers. The grafting and compatibilization reactions were confirmed using FTIR and ¹³C NMR spectroscopy. The properties of these blends were studied in detail by varying the amount of compatibilizer, and the improved mechanical behaviour was correlated with the morphology with the help of scanning electron microscopy. Morphology studies also revealed the interfacial interaction in the blend containing grafted PBT. The improvement in the properties of these blends can be attributed to the effective interaction of grafted maleic anhydride groups with the amino group in PA66. The results indicate that PBT‐g‐MA acts as an effective compatibilizer for the immiscible blends of PBT and PA66. © 2000 Society of Chemical Industry     

Evaluation of PP/EPDM nanocomposites filled with SiO2, TiO2 and ZnO nanofillers as thermoplastic elastomeric insulators

Abstract

Thermoplastic elastomer, which has important characteristics for cable insulation, was developed by melt blending of polypropylene (PP) with ethylene propylene diene monomer (EPDM) at various blend ratios together with SiO₂, TiO₂ and ZnO nanofillers at fixed loading of 2 vol.-%. The influence of EPDM content and the presence of nanofillers in the blend on burning rate, hydrophobicity and dielectric breakdown strength were investigated. Burning rate of PP/EPDM/ZnO was significantly reduced, implying that there was an improvement in fire retardancy with the addition of ZnO nanofillers in the polymer blend. Both SiO₂ and ZnO filled system showed an improvement in hydrophobicity. Furthermore, dielectric breakdown strength showed higher value in EPDM rich blends. In addition, the presence of nanofillers deteriorated the dielectric breakdown strength of PP/EPDM nanocomposites.     

Investigation of thermal behavior and decomposition kinetic of PET/PEN blends and their clay containing nanocomposites

Blends of Poly(ethylene terephthalate), (PET), and poly(ethylene naphthalene 2,6-dicarboxylate), (PEN), were prepared in a twin-screw extruder. Samples were investigated by differential scanning calorimetry (DSC) and proton nuclear magnetic resonance (¹H NMR) measurements to evaluate the extent of transesterification reaction. X-ray diffraction (XRD) test was performed to examine the effect of transesterification reactions on crystalline structure of the blends. Thermogravimetry analysis (TGA) was used to study thermal decomposition of the blends which could be explained by the level of transesterification reaction for various blend compositions. The kinetic of the decomposition reaction was analyzed by Freeman-Carroll and Chang models. It was found that these two methods were acceptable models for describing the thermal decomposition of the blends however, the Chang model showed better correlation with the experimental data as compared to the other model. Results revealed that progress of transesterification reaction in blends depends on temperature and mixing time, which have dominant role in thermal behavior and decomposition kinetic of the blends. Effect of nanoclay on transesterification reactions and degradation behavior was also investigated. It was found that the nanoclay inhibited the transesterification reactions and reduced the thermal stability of the blends. PET degraded much faster than PEN in O₂ environment while, an opposite trend was observed in N₂ atmosphere.     

噁唑啉官能化聚苯乙烯对PA66/PET共混物性能的影响

研究了(口恶)唑啉官能化聚苯乙烯(RPS)对聚酰胺66/聚对苯二甲酸乙二酯(PA 66/PET)共混物力学性能和相容性的影响。结果表明,RPS使该共混体系的力学性能和相容性有了明显的提高。组成为PA 66/PET/RPS(80:20:5)的共混物缺口冲击强度达15.7 kJ/m~2,相当于纯PA 66的3倍。