Effects of glass fiber on the properties of polyoxymethylene/thermoplastic polyurethane/multiwalled carbon nanotube composites

The effects of epoxy‐functionalized glass fiber (GF) on the electrical conductivity, crystallization behavior, thermal stability, and dynamic mechanical properties of polyoxymethylene (POM)/thermoplastic polyurethane (TPU)/multiwalled carbon nanotube (MWCNT) composites are investigated. The electrical resistivities of POM/5%−20% TPU/1% MWCNT composites are significantly reduced by nine orders of magnitude after the addition of 20% GF because of the formation of TPU‐coated GF structure facilitating the construction of conductive networks. GF has no obvious influence on the crystallization temperature, melting temperature, and degree of crystallinity of POM in POM/TPU/MWCNT composites because of their relatively bigger size compared with POM chains and MWCNTs. The storage moduli of POM/TPU/MWCNT composites are improved by the addition of GF, indicating that POM/TPU/MWCNT/GF composites are promising materials with good electrical and mechanical properties. POLYM. COMPOS., 38:1319–1326, 2017. © 2015 Society of Plastics Engineers     

Influence of thermooxidative aging on the static and dynamic mechanical properties of long‐glass‐fiber‐reinforced polyamide 6 composites

The static and dynamic mechanical properties, thermal behaviors, and morphology of pure long‐glass‐fiber‐reinforced samples [polyamide 6 (PA6)/long glass fiber (LGF)] with different thermal exposure times at 160°C were studied by comparison with stabilized samples in this study. The aging mechanism of the PA6/LGF samples under heat and oxygen was studied with the methods of thermal Fourier transform infrared (FTIR), differential scanning calorimetry, dynamic mechanical analysis, scanning electron microscopy (SEM), and so on. The results indicate that the static mechanical strength, melting temperature, and crystallization temperature decreased because of the decomposition of the macromolecular chain of PA6 resin and the debonding of the interface between the glass fibers and matrix. The glass‐transition temperature and crystallinity also increased and decreased, respectively, after aging. The macromolecular chain decomposition dominated in the subsequent aging process; this resulted in many sharp and brittle microcracks appearing on the surfaces of the aged samples, as shown by SEM and the FTIR spectra. The existence of stabilizers endowed the PA6/LGF composites with better retention of static and dynamic mechanical properties. The reason was that the metal ions of the copper salt antioxidant acted as an anti‐aging catalyst in the reinforced PA6 system. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39594.     

Mechanical,thermal and rheological properties of hollow glass microsphere filled thermoplastic polyurethane composites blended by normal vane extruder

In this study, different proportions of hollow glass microsphere (HGM) filled thermoplastic polyurethane (TPU) elastomer composites were prepared by normal vane extruder. The phase morphology, rheological properties, mechanical properties and thermal stability of TPU/HGM composites were investigated in detail. It was observed that the incorporation of HGM increased the thermal stability of TPU. With the increase in HGM content from 5 to 20?wt-%, the glass transition temperature, storage modulus and complex viscosity values increased continuously, while the density of the composite monotonously decreased. Moreover, the tensile modulus of the composites increased from 43.5 to 81.3?MPa. The results showed that, although raw HGM was used without any modification, the HGM played an important role in improving the properties of TPU.     

PP/LGF复合材料的膨胀性阻燃与协效阻燃性能

采用膨胀型阻燃剂(IFR)及协效剂海泡石(SP)对长玻璃纤维增强聚丙烯(PP/LGF)复合材料进行阻燃,通过双螺杆挤出机制备了PP/LGF母粒,IFR母粒和SP母粒,然后将这3种母粒通过注塑机制备了PP/LGF/IFR/SP复合材料,通过极限氧指数(LOI)、垂直燃烧测试、锥形量热仪、热重分析、扫描电子显微镜、力学性能测试等表征PP/LGF各阻燃复合体系的性能。结果表明,当IFR质量分数为22%时,PP/LGF/IFR阻燃复合材料的LOI为28.8%,且垂直燃烧等级达到V–0级;锥形量热仪测试结果表明加入IFR及SP后阻燃复合体系的第一热释放速率峰值降低,而第二热释放速率峰消失;SP质量分数为1%,IFR质量分数为21%的PP/LGF/IFR/SP阻燃复合材料LOI为29.6%,垂直燃烧等级达到V–0级,热释放速率峰值和总热释放量得到有效降低,热稳定性最好,且燃烧时产生致密的炭层覆盖于玻璃纤维表面,同时加入1%SP后复合材料的力学性能下降幅度相对较小。     

Performance of long glass fiber‐reinforced polypropylene composites at different injection temperature

Long glass fiber‐reinforced polypropylene composites were prepared using self‐designed impregnation device. Effects of the different injection temperature on mechanical properties, crystallization, thermal, and dynamic mechanical properties of long glass fiber‐reinforced polypropylene composites were discussed. The differential scanning calorimetry (DSC) results indicate that the melting peak temperature of PP/LGF composites gradually reduced, however, the crystallinity of PP/LGF composites gradually increased with increasing injection temperature. Thermo‐gravimetric analyzer (TGA) results demonstrate that with increasing injection temperature, the temperature of the PP/LGF composites melt increased, the viscosity of the PP/LGF composites melt lowered, the mold filling of the PP/LGF composites melt was easy, the shear force of glass fiber was relatively low, which made the residual length of glass fiber in products increase. Dynamic thermal mechanical analyzer (DMA) results show that the storage modulus of PP/LGF composites is the highest while the injection temperature is at 290°C, and the peak value of tan σ of PP /LGF composites at 290°C is minimal, which indicates that the mechanical properties of PP /LGF composites at 290°C is the best. What' more, the injection temperature at 290°C significantly ameliorated “glass fiber rich skin” of products of glass fiber‐reinforced composites. J. VINYL ADDIT. TECHNOL., 24:233–238, 2018. © 2016 Society of Plastics Engineers     

Tensile behavior of glass‐fiber‐filled polyacetal: Influence of the functional groups of polymer matrices

We investigated the tensile behavior of glass‐fiber‐filled polyacetal [i.e., polyoxymethylene (POM)], focusing on the mutual influence of the functional groups in the POM matrices and the glass binder system. The different POM matrices were compounded with three kinds of glass fibers (20 wt %) treated with different glass binders, namely, epoxy resin, thermoplastic polyurethane (TPU), and a mixture of TPU and epoxy resin. A good correlation between the tensile strength and elongation at break was observed, regardless of the difference in the glass binders. The composites based on the modified POM matrix, which had both a carboxyl end group and a hydroxyl end group, improved the tensile properties noticeably in comparison with those based on the normal POM matrix. The composites were strengthened with an increase in the concentration of the functional groups. The results of scanning electron microscopy observations indicated that the fractured surfaces of a specimen having maximum tensile strength and elongation exhibited cohesion of the modified POM on the surfaces of the glass fibers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Effect of impregnation time on performance of long glass fiber‐reinforced polypropylene composites

Long glass fiber (LGF)‐reinforced polypropylene (PP) composites were prepared using self‐designed impregnation device. Effects of impregnation time on mechanical properties, crystallization, dynamic mechanical properties, and morphology of PP/LGF composites were investigated. The experiment results demonstrate that the excellent tensile strength, Notched Izod impact strength was 152.9 MPa, 31.2 KJ/m², respectively, and the stiffness of PP/LGF composites was higher, when the impregnation time was 7.03 s. The excellent interfacial adhesion between PP and glass fiber indicates that PP/LGF composites possess the outstanding mechanical properties. The impregnation time scarcely influenced thermal properties of PP/LGF composites. J. VINYL ADDIT. TECHNOL., 24:174–178, 2018. © 2016 Society of Plastics Engineers     

长玻纤增强PET复合材料的力学性能研究

采用自制的浸润装置，以PET浸渍长波纤，经切粒后得到长度为6mm的长纤维增强PET预浸料切片，经一定温度热处理，可得到长纤增强PET复合材料。研究了注塑样条中玻纤含量对其力学性能及玻纤长度分布的影响，并采用SEM观察了长玻纤增强PET注塑样条的断面形貌。结果表明，复合材料力学性能随玻璃纤维含量的提高均有不同程度的提高，当玻纤的质量分数在40％～50％时，力学性能基本达到最佳，且由本方法制备的长玻纤增强PET复合材料的力学性能已达到并超过了国外同类产品的水平。     

长玻纤增强丙烯腈-苯乙烯复合材料的研制

采用熔体浸渍工艺制备了长玻纤增强丙烯腈-苯乙烯共聚物复合材料(LGF/AS),研究了不同玻纤含量对LGF/AS复合材料力学、动态力学性能和形态的影响。结果表明:随着玻璃纤维含量的提高,LGF/AS复合材料的力学和动态力学性能逐渐增加;通过SEM证明了玻璃纤维在基体树脂中的具有良好的分散性。     

Thermal stability and thermal degradation kinetics of short and long glass fiber reinforced PA10T composites

In this work, the long glass fiber reinforced poly(decamethylene terephthalanide) (PA10T/LGF) composites and short glass fiber reinforced PA10T (PA10T/SGF) composites were prepared by two different extrusion processing methods, respectively. The results of mechanical properties reveal the introduction of glass fiber can improve the performance of the material, and the LGF reinforced PA10T composites can achieve much higher performance than the SGF reinforced ones at the same level of fiber contents. The thermal stabilities of neat PA10T, PA10T/SGF, and PA10T/LGF are investigated by nonisothermal TG analysis. The thermal degradation kinetics is introduced by using Kissinger and Flynn‐Wall‐Ozawa methods and the thermal degradation mechanism functions of the samples are calculated by the Coats‐Redfem model. The results show that the thermal stabilities of PA10T/SGF and neat PA10T are better than that of PA10T/LGF. In addition, the incorporation of glass fiber into PA10T do not have much effect on the reaction mechanism type of thermal degradation compared with that neat PA10T. Furthermore, the thermal stability analysis of the composites is verified by the computed results of Gibbs free energy (ΔG^#). POLYM. ENG. SCI., 59:246–253, 2019. © 2018 Society of Plastics Engineers     

聚氨酯/纳米碳酸钙改性聚甲醛的研究

采用机械共混方法,制备了聚甲醛/热塑性聚氨酯/纳米碳酸钙(POM/TPU/nano-CaCO3)复合材料。研究了TPU/nano-CaCO3配比及用量对复合材料力学性能的影响,并用差热分析仪(DSC)及偏光显微镜(PLM)对复合材料的结晶性能和微观形态结构进行了分析。结果表明:当TPU与nano-CaCO3的总用量为10份,其中TPU与nano-CaCO3的质量比为7:3时,体系的缺口冲击强度出现最大值12.84kJ/m2,比纯POM提高了88.5%。同时TPU和nano-CaCO3的加入降低了POM的结晶度,缩小了球晶尺寸。     

剑麻纤维/长玻纤混杂增强PP复合材料的力学性能研究

采用剑麻纤维(SF)和长玻璃纤维(LGF)混杂增强聚丙烯(PP)复合材料,考察了SF/LGF的比例和含量对PP复合材料力学性能的影响。结果表明:SF/LGF在聚丙烯树脂基体中呈交叉网状分布,这有利于提高复合材料的冲击强度、弯曲模量、拉伸强度和软化点。在SF/LGF质量比为2 2∶,二者总质量分数为30%时,SF/LGF混杂增强PP复合材料的综合力学性能较好。     

Morphology and properties of renewable poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) blends with thermoplastic polyurethane

Poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)/thermoplastic polyurethane (PHBV/TPU) composites were prepared by solution blending combined with melt processing in an effort to improve the toughness of PHBV and overcome the coalescence phenomena of TPU at the same time. The compatibility, cross‐section morphology, crystal structure, thermal behaviour, and mechanical properties of composites were investigated. Field emission scanning electron microscopy results showed that no distinct interface was found in composites, uniformly dispersed PHBV/TPU composites were obtained. The incorporation of TPU did not change the basic crystalline structure of PHBV, but decreased its crystallinity. What's more, the integrity of PHBV spherulites structure was destroyed and the radial growth rate of spherulites was inhibited. Differential scanning calorimetry results analyzed by Jeziorny method indicated that the nucleation mode of composites did not change. Besides, when TPU content was up to 40 wt%, the initial degradation temperature of PHBV/TPU composite was increased by 5°C, and the elongation‐at‐break was increased by 225% compared with those of PHBV. POLYM. ENG. SCI., 54:1113–1119, 2014. © 2013 Society of Plastics Engineers     

The influence of filler treatment on the properties of TPU/PP blends: I. Thermal properties and stability

Commercially available organosilane (3‐glycidoxypropyltrimethoxysilane (GPTMS)) coupling agent was used to treat talc in order to improve the affinity relative between the filler and the polymer in composites as well as filler and polymer in the thermoplastic polyurethane/polypropylene (TPU/PP) blends (talc content was 5 wt%). The talc particles were first modified with GPTMS and then introduced into TPU, PP as well as TPU/PP blends with different weight ratios of polymers using blending method and subsequently injection molded in a hydraulic press. The aim was to report the effect of silane coupling agent on the thermal and morphological properties of talc filled composites and blends. The results showed that the thermal properties of the TPU, PP composites and TPU/PP blends were improved with the addition of silane treated talc (higher melting (T_m), crystallization (T_c) temperatures and degree of crystallinity (χ_c)). The glass transition temperature (T_g) obtained by dynamic mechanical analysis (DMA) of the TPU soft segments in TPU/PP blends increased with the addition of untreated and silane treated talc due to lower mobility of the soft segments in TPU and better miscibility of TPU and PP. TPU/PP blends with the silane treated talc show better thermal stability than the TPU/PP blends with untreated talc. POLYM. ENG. SCI., 55:1920–1930, 2015. © 2014 Society of Plastics Engineers     

Preparation and characterization of thermoplastic polyurethane/organoclay nanocomposites by melt intercalation technique: Effect of nanoclay on morphology,mechanical, thermal,and rheological properties

Nanocomposites based on thermoplastic polyurethane (TPU) and organically modified montmorillonite (OMMT) were prepared by melt blending. Organically modified nanoclay was added to the TPU matrix in order to study the influence of the organoclay on nanophase morphology and materials properties. The interaction between TPU matrix and nanofiller was studied by infrared spectroscopy. Morphological characterization of the nanocomposites was carried out using X‐ray diffraction, transmission electron microscopy, and scanning electron microscopy techniques. The results showed that melt mixing is an effective process for dispersing OMMT throughout the TPU matrix. Nanocomposites exhibit higher mechanical and thermal properties than pristine TPU. All these properties showed an increasing trend with the increase in OMMT content. Thermogravimetric analysis revealed that incorporation of organoclay enhances the thermal stability of nanocomposites significantly. Differential scanning calorimetry was used to measure the melting point and the glass transition temperature (T_g) of soft segments, which was found to shift toward higher temperature with the inclusion of organoclays. From dynamic mechanical thermal analysis, it is seen that addition of OMMT strongly influenced the storage and loss modulus of the TPU matrix. Dynamic viscoelastic properties of the nanocomposites were explored using rubber process analyzer. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and characterization of carbon nanofiber reinforced thermoplastic polyurethane nanocomposites

The effect of CNFs on hard and soft segments of TPU matrix was evaluated using Fourier transform infrared (FTIR) spectroscope. The dispersion and distribution of the CNFs in the TPU matrix were investigated through wide angle X‐ray diffraction (WAXD), field emission scanning electron microscope (FESEM), high resolution transmission electron microscope (HRTEM), polarizing optical microscope (POM), and atomic force microscope (AFM). The thermogravimetric analysis (TGA) showed that the inclusion of CNF improved the thermal stability of virgin TPU. The glass transition temperature (T_g), crystallization, and melting behaviors of the TPU matrix in the presence of dispersed CNF were observed by differential scanning calorimetry (DSC). The dynamic viscoelastic behavior of the nanocomposites was studied by dynamical mechanical thermal analysis (DMTA) and substantial improvement in storage modulus (E') was achieved with the addition of CNF to TPU matrix. The rheological behavior of TPU nanocomposites were tested by rubber processing analyzer (RPA) in dynamic frequency sweep and the storage modulus (G') of the nanocomposites was enhanced with increase in CNF loading. The dielectric properties of the nanocomposites exhibited significant improvement with incorporation of CNF. The TPU matrix exhibits remarkable improvement of mechanical properties with addition of CNF. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of Barium Titanate on the Thermal,Morphology, Surface,and Mechanical Properties of the Thermoplastic Polyurethane/Barium Titanate Composites

The aim of this study was to improve thermal stability, mechanical, and surface properties of thermoplastic polyurethane (TPU) with the addition of BaTiO₃. The TPU/BaTiO₃ composites having various ratios of TPU and BaTiO₃ were prepared. The chemical structure of the prepared composites was investigated by FTIR. Thermal stability of the samples were evaluated by thermogravimetric analysis and differential scanning calorimetry. Mechanical properties of the samples were characterized with stress–strain test. Hydrophobicity of the samples was determined by the contact angle measurements. Moreover, the surface morphology of the samples was investigated by a scanning electron microscopy.     

Improving the thermal and mechanical properties of poly(propylene carbonate) by incorporating functionalized graphite oxide

Poly(propylene carbonate) (PPC) is a new biodegradable aliphatic polycarbonate. However, the poor thermal stability, low glass transition temperatures (T_g), and relatively low mechanical property have limited its applications. To improve the thermal and mechanical properties of PPC, functionalized graphite oxide (MGO) was synthesized and mixed with PPC by a solution intercalation method to produce MGO/PPC composites. A uniform structure of MGO/PPC composites was confirmed by X‐ray diffraction and scanning electron microscope. The thermal and mechanical properties of MGO/PPC composites were investigated by thermal gravimetric analysis, differential scanning calorimetric, dynamic mechanical analysis, and electronic tensile tester. Due to the nanometer‐sized dispersion of layered graphite in polymer matrix, MGO/PPC composites exhibit improved thermal and mechanical properties than pure PPC. When the MGO content is 3.0 wt %, the MGO/PPC composites shows the best thermal and mechanical properties. These results indicate that nanocomposition is an efficient and convenient method to improve the properties of PPC. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

POM/GF-MWCNTs复合材料的制备及其性能研究

将经γ氨丙基三乙氧基硅烷（KH550）处理后的多壁碳纳米管（MWCNTs）接枝到玻璃纤维（GF）表面,制成GF-MWCNTs复合填料,通过双螺杆挤出机熔融共混制备出聚甲醛（POM）/GF-MWCNTs复合材料,并对其力学性能、热性能及电性能进行了测试。结果表明,GF-MWCNTs添加量较低时,复合材料的拉伸强度和缺口冲击强度都有所提高,且分别在3 %（质量分数,下同）和1 %时达到最大值,之后则随着填料含量的增加而不断降低;当GF-MWCNTs的添加量达到10 %时,复合材料的拉伸强度和缺口冲击强度已然低于纯POM;加入GF-MWCNTs提高了复合材料的热稳定性,使POM的结晶温度和结晶度提高;GF-MWCNTs能降低复合材料的体积电阻率,但由于未在POM基体中形成逾渗网络,复合材料导电性提高并不明显。     

Effects of thermoplastic polyurethane on the properties of poly(lactic acid)/organo‐montmorillonite nanocomposites based on novel vane extruder

Polylactic acid (PLA)/organo‐montmorillonite (OMMT) nanocomposites toughened with thermoplastic polyurethane (TPU) were prepared by melt‐compounding on a novel vane extruder (VE), which generates global dynamic elongational flow. In this work, the mechanical properties of the PLA/TPU/OMMT nanocomposites were evaluated by tensile, flexural, and tensile tests. The wide‐angle X‐ray diffraction and transmission electron microscopy results show that PLA/TPU/OMMT nanocomposites had clear intercalation and/or exfoliation structures. Moreover, the particles morphology of nanocomposites with the addition of TPU was investigated using high‐resolution scanning electronic microscopy. The results indicate that the spherical TPU particles dispersed in the PLA matrix, and the uniformity decreased with increasing TPU content (≤30%). Interestingly, there existed abundant filaments among amount of TPU droplets in composites with 30 and 40 wt% TPU. Furthermore, the thermal properties of the nanocomposites were examined with differential scanning calorimeter and dynamic mechanical analysis. The elongation at break and impact strength of the PLA/OMMT nanocomposites were increased significantly after addition of TPU. Specially, Elongation at break increased by 30 times, and notched impact strength improved 15 times when TPU loading was 40 wt%, compared with the neat PLA. Overall, the modified PLA nanocomposites can have greater application as a biodegradable material with enhanced mechanical properties. POLYM. ENG. SCI., 54:2292–2300, 2014. © 2013 Society of Plastics Engineers