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1.
This article mainly investigated the length distributions of the alkali‐free short glass fibers in specimens and their effect on the mechanical and thermal properties of the composites. The results show that the initial length, addition level and feed way of the fibers have obvious effects on the length distributions of fibers in specimens, and thereby the mechanical and thermal properties of the composites. The main‐direction feed way has an intense shear action on the fibers in specimens. With the increase of the fiber content, the reinforcing effect of fibers on the tensile strength, flexural strength and flexural modulus of the composites is increased, while the impact strength is decreased first and then tends to be stable, and the strength factor (F) of the tensile strength to weld line is significantly reduced. The longer the fiber lengths in specimens are, the more obvious the reinforcing and toughening effects are. To some extent, with the increase of the fiber content, the storage modulus (E′) and loss modulus (E′′) of the specimens are increased, but the loss factor (Tan δ) is reduced. The effect of the fiber initial lengths on the heat‐degradation of composites is smaller than that of the fiber content. Meanwhile, adding fibers can improve the thermal stability of the composites, and this law is also confirmed by the heat deflection temperature (HDT) test. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40697. 相似文献
2.
Two series of biodegradable polymer blends were prepared from combinations of poly(L ‐lactide) (PLLA) with poly(?‐caprolactone) (PCL) and poly(butylene succinate‐co‐L ‐lactate) (PBSL) in proportions of 100/0, 90/10, 80/20, and 70/30 (based on the weight percentage). Their mechanical properties were investigated and related to their morphologies. The thermal properties, Fourier transform infrared spectroscopy, and melt flow index analysis of the binary blends and virgin polymers were then evaluated. The addition of PCL and PBSL to PLLA reduced the tensile strength and Young's modulus, whereas the elongation at break and melt flow index increased. The stress–strain curve showed that the blending of PLLA with ductile PCL and PBSL improved the toughness and increased the thermal stability of the blended polymers. A morphological analysis of the PLLA and the PLLA blends revealed that all the PLLA/PCL and PLLA/PBSL blends were immiscible with the PCL and PBSL phases finely dispersed in the PLLA‐rich phase. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
3.
Single wool fibers were coated with TiO2 by using the sol‐gel method. The uniaxial tensile properties of TiO2 coated single wool fibers heated at different temperatures from 25 to 200°C were investigated and compared with those of uncoated single wool fibers. It was observed that the shape of the stress–strain curve of TiO2 coated wool fibers became the same as uncoated wool fibers and showed a similar tendency of change to uncoated wool fibers with increasing temperature. But, the TiO2 coated wool fibers obtained higher rigidity than uncoated wool fibers and up to their rupture points; they obtained higher stress levels in three deformation regions in the stress–strain curves, which indicates stronger wool fibers. Although the breaking extension of TiO2 coated wool fibers decreased little by about 8%, the Young's modulus of TiO2 coated wool fibers increased significantly by 19%, which was caused mostly by an increment in the stiffness of the cuticle layer of the wool fiber, and remained relatively higher than that of uncoated wool fibers after heat treatments. Structural changes in both uncoated and TiO2 coated single wool fibers due to thermal effect, which caused the changes in the uniaxial tensile properties and the thermal behaviors of these fibers were discussed by using spectroscopic and thermal analysis methods in detail. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 898‐907, 2013 相似文献
4.
The heat‐resistant copolymer of N‐phenylmaleimide (NPMI)–styrene (St)–maleic anhydride (MAH) was synthesized in xylene at 125°C with di‐tert‐butyl diperoxyterephthalate as an initiator. The characteristics of the copolymer were analyzed by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy (1H‐NMR and 13C‐NMR), gel permeation chromatography, and elemental analysis. The 13C‐NMR results show that the copolymer possessed random sequence distribution; this was also supported by the differential scanning calorimetry experiment, in which a single glass‐transition temperature (Tg) of 202.3°C was observed. The thermal stability and degradation mechanism of the copolymer were investigated by thermogravimetric analysis. Using the Kissinger equation and Ozawa equation, we proved a nucleation controlling mechanism with an apparent activation energy of 144 kJ/mol. Blends of acrylonitrile–butadiene–styrene with the NPMI–St–MAH copolymer with various contents were prepared with a twin‐screw extruder processes. The mechanical and thermal properties of the materials, such as the tensile and flexural strength, Tg's, and Vicat softening temperatures, were all enhanced with the addition of the modifier, whereas the melt flow index decreased. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
5.
Sanja Mahović Poljaček Dino Priselac Urška Stanković Elesini Mirjam Leskovšek Mirela Leskovac 《Polymer Engineering and Science》2021,61(9):2295-2310
In this research, biodegradable blend of poly(ɛ-caprolactone) (PCL) and poly(lactic acid) (PLA) is proposed as a new material for the production of a printing plate for embossing process. Printing plates for embossing consist of raised printing elements and recessed nonimage elements. In production of printing plates, laser technology was used in order to form a relief printing plate. The embossing process is based on the principle of the pressure of the relief printing plate into the printing substrate, which causes the controlled deformation of the substrate and three-dimensional (3D) effect. Coir fibers (CFs) were added as a natural filler to PCL/PLA blends to improve and adjust the properties of produced blends. Scanning electron microscopy micrographs, dynamic mechanical analysis analysis, roughness, and hardness were measured on prepared materials, and 2D and 3D microscopy was conducted on laser engraved printing plates. Results have shown that the addition of CFs improved the mechanical properties of produced materials. DMA results indicate the semicrystalline structure of all prepared blends, and that the addition of CFs raises the elasticity of the composites. Laser engraving showed that it is possible to engrave the produced biodegradable materials and to use it as a material for production of printing plates. 相似文献
6.
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. 相似文献
7.
In present work, novel phthalonitrile end-capping poly(arylene ether nitrile)-phenyl (PEN-Ph) films with excellent mechanical properties as well as high glass transition temperature were prepared through blending high-molecular-weight PEN-Ph (HMW PEN-Ph) and low-molecular-weight PEN-Ph (LMW PEN-Ph). Then, the thermal and mechanical properties of the samples with different mass ratio of HMW PEN-Ph and LMW PEN-Ph were studied, and the effect of heat-treatment temperature on the performance of films was also investigated. The analysis results indicate that the crosslinking density as well as film formation can be controlled by adjusting the mass ratio of HMW PEN-Ph to LMW PEN-Ph. Besides, when the mass ratio of HMW PEN-Ph to LMW PEN-Ph is 5:2, the film treated at 340 °C possesses the best thermal and mechanical properties, with Tg of 218.9 °C and tensile strength of 104.8 MPa, increased by 10.9 °C and 16.6 MPa than pure HMW PEN-Ph film, respectively. Thus, the presence of LMW PEN-Ph makes the thermal and mechanical properties of the films improve dramatically, providing the possibility for the application in the electronics and high-temperature resistant fields. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48457. 相似文献
8.
As the material properties of acrylonitrile–butadiene–styrene copolymer (ABS) have an excessively wide margin for applications in automobile console boxes, ABS partly replaced with poly(l ‐lactic acid) (PLA) may be used for the same purpose with improved ecofriendliness if the corresponding deterioration of the material properties is acceptable through the choice of appropriate additives. ABS composites with 30 wt % renewable components (PLA and cellulose pulp) were prepared by melt compounding, and the material properties were examined as a function of the additive content. The changes in the mechanical properties of the ABS/PLA blends were examined after the addition of cellulose pulp and two clays [Cloisite 25A (C25A) and sodium montmorillonite] as well as these two clays treated with bis(3‐triethoxysilylpropyl)tetrasulfide (TESPT). The heat distortion temperatures of the composites were measured as a function of the content of the TESPT‐treated C25A. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40329. 相似文献
9.
《应用聚合物科学杂志》2017,134(6)
Novel poly(methyl methacrylate) (PMMA)/silica aerogel bimodal cellular foams were prepared by melt mixing and a supercritical carbon dioxide foaming process. The effects of the silica aerogel content on the morphologies and thermal‐insulating and mechanical properties of the foams were investigated by scanning electron microscopy, mechanical tests, and heat‐transfer analysis. The experimental results show that compared to the pure PMMA foam, the PMMA/silica aerogel microcellular foams exhibited more uniform cell structures, decreased cell sizes, and increased cell densities (the densities of the foams were 0.38–0.45 g/cm3). In particular, a considerable number of original nanometric cells (ca. 50 nm) were evenly embedded in the cell walls and on the inner surfaces of the micrometric cells (<10 μm). A 62.7% decrease in the thermal conductivity (0.072 W m−1 K−1) in comparison to that of raw PMMA after 0.5 wt % silica aerogel was added was obtained. Mechanical analysis of the PMMA/silica aerogel foams with 5 and 2 wt % silica aerogel showed that the compressive and flexural strengths were distinctly improved by 92 and 52%, respectively, and the dynamic storage moduli increased. The enhanced performance showed that with the addition of silica aerogel into PMMA, one can obtain thermal‐insulation materials with a favorable mechanical strength. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44434. 相似文献
10.
Byung Min Satish Kumar Michael R. Hibbs Hongming Ma David M. Collard David A. Schiraldi 《应用聚合物科学杂志》2004,93(4):1793-1803
Blends of poly(ethylene terephthalate) (PET) and poly(ethylene terephthalate‐co‐4,4′‐ bibenzoate) (PETBB) are prepared by coextrusion. Analysis by 13C‐NMR spectroscopy shows that little transesterification occurs during the blending process. Additional heat treatment of the blend leads to more transesterification and a corresponding increase in the degree of randomness, R. Analysis by differential scanning calorimetry shows that the as‐extruded blend is semicrystalline, unlike PETBB15, a random copolymer with the same composition as the non‐ random blend. Additional heat treatment of the blend leads to a decrease in the melting point, Tm, and an increase in glass transition temperature, Tg. The Tm and Tg of the blend reach minimum and maximum values, respectively, after 15 min at 270°C, at which point the blend has not been fully randomized. The blend has a lower crystallization rate than PET and PETBB55 (a copolymer containing 55 mol % bibenzoate). The PET/PETBB55 (70/30 w/w) blend shows a secondary endothermic peak at 15°C above an isothermal crystallization temperature. The secondary peak was confirmed to be the melting of small and/or imperfect crystals resulting from secondary crystallization. The blend exhibits the crystal structure of PET. Tensile properties of the fibers prepared from the blend are comparable to those of PET fiber, whereas PETBB55 fibers display higher performance. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1793–1803, 2004 相似文献
11.
B. Sreedhar M. Sairam D. K. Chattopadhyay P. A. Syamala Rathnam D. V. Mohan Rao 《应用聚合物科学杂志》2005,96(4):1313-1322
Starch–poly(vinyl alcohol) (PVA) blends with different compositions were prepared and crosslinked with borax by in situ and posttreatment methods. Various amounts of glycerol and poly(ethylene glycol) with a molecular weight of 400 were added to the formulations as plasticizers. The pure starch–PVA blends and the crosslinked blends were subjected to differential scanning calorimetry, thermogravimetry, and X‐ray photoelectron spectroscopic studies. Broido and Coats–Redfern equations were used to calculate the thermal decomposition kinetic parameters. The tensile strengths and elongation percentages of the films were also evaluated. The results suggested that the glass‐transition temperature (Tg) and the melting temperature strongly depended on the plasticizer concentration. The enthalpy relaxation phenomenon was dependent on the starch content in the pure blend. The crosslinked films showed higher stability and lower Tg's than pure PVA and starch–PVA blends, respectively. High‐resolution X‐ray photoelectron spectroscopy provided a method of differentiating the presence of various carbons associated with different environments in the films. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1313–1322, 2005 相似文献
12.
The article describes the effect of structure of vinyl ester resins (VE) on the mechanical properties of neat sheets as well as glass fabric‐reinforced composites. Different samples of VE were prepared by reacting ester of hexahydrophthalic anhydride (ER) and methacrylic acid (MAA) (1 : 1 molar ratio) followed by reaction of monomethacrylate terminated epoxy resin with glutaric (E) or adipic (F) or sebacic acid (G) (2 : 1 molar ratio). The neat VE were diluted with styrene and sheets were fabricated by using a glass mold. A significant reduction in the mechanical properties was observed by increasing the methylene content of resin backbone (i.e., sample E to G). Glass fabric‐reinforced composites were fabricated by vacuum assisted resin transfer molding (VARTM) technique. Resin content in the laminates was 50 ± 5 wt %. Increase in the number of methylene groups in the vinyl ester resin (i.e., increasing the bridge length) did not show any significant effect on limiting oxygen index (LOI) value (21 ± 1) of the laminates but tensile strength, tensile modulus, flexural strength, and flexural modulus all increased though these values are significantly lower than observed in laminates based on resin B. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
13.
Kenaf (KNF)‐filled polypropylene/waste tire dust (PP/WTD) composites containing different KNF loadings (0, 5, 10, 15, and 20 parts per hundred parts of resin (phr)) were prepared using a Thermo Haake Polydrive internal mixer. The influence of the KNF form (KNF short fiber (KNFs) and KNF powder (KNFp)) at different KNF loadings on properties of the composites was studied. Results showed that with increasing KNF loading, the stabilization torque, tensile modulus, water absorption, and thermal properties increased for both KNFp‐ and KNFs‐filled PP/WTD composites. However, the tensile strength and elongation at break decreased by 29.2% and 53.9%, respectively, for KNFp‐filled PP/WTD composites, whereas KNFs‐filled PP/WTD composites showed a decrement of 24.5% and 63.5%, respectively. The stabilization torque, tensile strength, and tensile modulus increased by 22.4%, 6.7%, and 2.6%, respectively, for KNFs‐filled PP/WTD composites at 20 phr KNF loading. The scanning electron microscopy morphological studies on the tensile fractured surfaces revealed poor adhesion between KNFp and PP/WTD matrices as compared to KNFs and PP/WTD matrices. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40877. 相似文献
14.
Mariana Desireé Reale Batista Lawrence T. Drzal Alper Kiziltas Deborah Mielewski 《Polymer Composites》2020,41(3):1074-1089
Cellulose fibers are attracting considerable attention within the transportation industry as a class of reinforcing agents for polymer composites owing to their low cost, low density, high mechanical properties, and considerable environmental benefits. The objective of this study was to develop hybrid composites combining cellulose fiber with long glass fiber (LGF), short glass fiber (SGF), or talc in a polypropylene (PP) matrix to optimize the overall composite properties. Tensile, flexural, and notched Izod impact tests revealed that in general the mechanical properties decreased with increasing cellulose content, however, adding an optimum concentration of the cellulose fiber is a promising alternative to reduce or replace the utilization of inorganic fibers. Hybrid composites with 15 wt% LGF and 15 wt% Cellulose A exhibited an increase of 86% and 252% in tensile stress and Young's modulus, respectively, compared to neat PP X. Regarding the impact strength and the temperature at the maximum rate of decomposition, hybrid composites with 15 wt% SGF and 15 wt% Cellulose B exhibited 23% and 17% increase, respectively, compared to neat PP Z. The crystallization temperature (Tc) of all the composites increased compared to neat PP, revealing the fibers ability to act as nucleating agents and speed rate of part production which will result in lowering the manufacturing cost. For applications in automotive “under-the-hood” and body interior components, the hybrid cellulose-inorganic reinforcement composite approach not only leads to superior weight and cost savings, but also environment benefits over the inorganic reinforced composites. 相似文献
15.
To improve the processability and properties of the poly(phenylene sulfide) (PPS) fibers at room temperature and high temperatures, a series of composite fibers based on PPS and multiwalled carbon nanotubes were prepared by melt spinning. We researched the processability with a high‐pressure capillary rheometer, and the properties of the composite fibers were investigated in detail by scanning electron microscopy, differential scanning calorimetry, fiber sonic velocity measurement, and single‐fiber strength testing. The results show that the carbon nanotubes (CNTs) had good interfacial adhesion with PPS and dispersed homogeneously in the PPS matrix. When the shear rate was higher than 500 s?1, the oriented CNTs induced the orientation of PPS molecular chains; this resulted in a decline in the apparent viscosity and an increase in the orientation degree of the molecular chains. Meanwhile, the CNTs acted as nucleating agents to effectively improve the crystallization of PPS. The strength of the fibers at room temperature were improved by 28.8% after the addition of 0.2% CNTs, and the initial modulus was also significantly enhanced. The strength retention at 160 °C was promoted from 60.58 to 88.32% with the addition of 1.0% CNTs. The shrinking percentage decreased to almost zero from higher than 15%; this suggested that the CNTs could efficiently improve the dimensional stability at high temperatures. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44609. 相似文献
16.
Natural fibers are rich in cellulose and they are a cheap, easily renewable source of fibers with the potential for polymer reinforcement. The presence of large amounts of hydroxyl groups makes natural fibers less attractive for reinforcement of polymeric materials. Composites made from polystyrene (PS)/styrene butadiene rubber (SBR) blend and treated rice husk powder (RHP) were prepared. The RHP was treated by esterification and acetylation. A similar series of composites was also prepared using maleic anhydride–polypropylene (MA–PP) as a coupling agent. The processing behavior, mechanical properties, effect of thermooxidative ageing, and surface morphology of untreated and chemically modified RHP were studied. There was a decrease in tensile strength (except MA–PP composites), elongation at break, and Young's modulus in chemically treated RHP composites. The postreaction process during thermooxidative ageing enhanced the tensile strength and Young's modulus of the esterified and MA–PP composites. Acetylation treatment was effective in reducing the percentage of water absorption in RHP/PS–SBR composites. In general chemically treated RHP/PS–SBR composites and MA–PP showed a better matrix phase and filler distribution. However, the degree of filler–matrix interaction was mainly responsible for the improvement of mechanical properties in the composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3320–3332, 2004 相似文献
17.
Acrylic fibers [polyacrylonitrile (PAN) fibers] have excellent flame‐retardant properties after they are modified by hydrazine hydrate and metal ions; however, their widespread applications are restricted because of poor mechanical properties. To improve the mechanical properties of these modified PAN fibers, poly(vinyl alcohol) (PVA) was added to the spinning solution of PAN as an effective reinforcing agent. The structure of the fibers before and after modification was studied by Fourier transform infrared spectroscopy, scanning electron microscopy, energy‐dispersive spectroscopy, and wide‐angle X‐ray diffraction. The mechanical properties and flame resistance of the fibers after treatment were also tested by a single‐fiber tensile tester and a limiting oxygen index (LOI) analyzer, respectively. We found that the LOI of the modified fibers was reduced from 54.7 to 29.1 after the introduction of 50 wt % PVA; however, the tensile strength was dramatically improved from about 1.50 cN/dtex to more than 4.00 cN/dtex. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43006. 相似文献
18.
Diana Gregor‐Svetec 《应用聚合物科学杂志》2000,75(10):1211-1220
The mechanical properties of multifilament yarns, spun from the blends of a plastic‐grade polymer with a fiber‐grade CR‐polymer in the composition range of 10–50 wt % added, were investigated. The predicted modulus of a two‐phase blend, calculated from several representative equations, was compared with the elastic modulus of drawn yarns, determined from the stress vs. strain curve and dynamic modulus obtained from the sound velocity measurements. The best fit was achived with the Kleiner's simplex equation. For both the static and dynamic elastic modulus, the largest negative deviation is seen at the 80/20 and 60/40 plastic/fiber‐grade polymer blend composition, while the largest positive deviation is seen at the 90/10 plastic/fiber‐grade polymer blend composition, suggesting good compatibility of both polymers, when only a small percent of the fiber‐grade CR‐polymer is added. Improved spinnability and drawability of blended samples led to the yarns with the tensile strength over 8 cN/dtex, elastic modulus over 11 GPa and dynamic modulus over 15.5 GPa. Structural investigations have shown that the improved mechanical behavior of blended samples, compared to the yarn spun from the pure plasic‐grade polymer, is the consequence of a higher degree of crystallinity, and above all, of a much higher orientation of macromolecules. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1211–1220, 2000 相似文献
19.
Gyuldzhan Yakub Antoniya Toncheva Nevena Manolova Iliya Rashkov Dobri Danchev Veselin Kussovski 《应用聚合物科学杂志》2016,133(5)
New microfibrous materials from polylactide and polyvinylpyrrolidone or polyethylene glycol loaded with the natural polyphenolic compound curcumin have been prepared by one‐pot electrospinning. The incorporation of curcumin in the fibers contributes to shielding curcumin from photodestruction and to enhancement of the mechanical properties of the fibers. Moreover, the formation of hydrogen bonds between curcumin and polyvinylpyrrolidone or polyethylene glycol facilitates the drug release. Curcumin release provides for the antibacterial and anticoagulant activity of the curcumin‐loaded mats and prevents adhesion and aggregation of platelets onto the surface of the mats. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42940. 相似文献
20.
Blends of semicrystalline Nylon 6 with a varying ratios of amorphous Nylon are studied for their morphological, thermal, dielectric, and mechanical behavior. Thermal analysis indicated a compositional dependant decrease in the melting and crystallization temperatures of Nylon 6. The blends exhibited a single compositional dependant glass transition temperature in dynamic mechanical thermal analysis and dielectrical relaxation spectroscopy over entire mixing ratio indicating miscibility between the blend components. The values of flexural modulus and tensile modulus of the blends are found to increase without significant loss in the impact properties. The water absorption of the blends is also lower than the values calculated by rule of mixtures. The observed synergistic behavior of the mechanical properties of the blends is indicative of presence of strong interactions in the blends components. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献