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Yoo Jae Maeng Byung Seon Yoon Moon Ho Suh Suck Hyun Lee Wan Bin Im 《Polymer Composites》2000,21(1):41-50
Long fiber molding materials are expected to play an important role in the near future. This paper describes a series of experiments performed to examine properties of ternary blends containing glass fiber (GF), polyamide (PA), and polypropylene (PP). The continuous glass fiber was impregnated with one of the blend constituent polymers by our specially designed impregnation apparatus and cut into chips of 6 mm length. These chips and the other polymer were used to produce various testing specimens in a twin screw extruder or in injection molding machine. The results indicated that the effect of fiber addition on the mechanical and rheological properties is clearly dependent on the order of impregnation process. In the blends containing the GF/PA + PP, the GFs are preferentially encapsulated with PA, and therefore the mechanical properties are superior to the blends with the GF/PP + PA in which the PP phase is located surrounding the GFs. This improved wetting of fibers by sequential impregnation not only resulted in better properties but also protected the fibers from shear action of the screw, thereby allowing significant increase in average fiber length to be achieved in the injection molding process. 相似文献
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The relation between the dynamic mechanical properties and the morphology of polypropylene (PP) block copolymers and polypropylene/elastomer blends was studied by dynamic mechanical analysis (DMA), light- and electron microscopy. The latter techniques contributed to an improvement in assignments of relaxation transitions in the DMA spectra. It was established that PP block copolymers had multiphase structure since the ethylene/propylene rubber phase (EPR) formed in the copolymerization contained polyethylene (PE) domains. An identical morphology was found in the case of PP/polyolefin thermoplastic rubber (TPO) blends. Impact modification of PP by styrene/butadiene block copolymers led to a multiphase structure, too, due to the polystyrene (PS) domains aggregated in the soft rubbery polybutadiene phase. In the semicrystalline polyolefinic and in the amorphous styrene/butadienebased thermoplastic rubbers, PE crystallites and PS do mains acted as nodes of the physical network structure, respectively. PP/EPDM/TPO ternary blends developed for replacing high-density PE showed very high dispersion of the modifiers as compared to that of PP block copolymers. This fine dispersion of the impact modifier is a basic regulating factor of impact energy dissipation in the form of shear yielding and crazing. 相似文献
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考察了玻璃纤维(GF)增强高结晶聚丙烯(PP)的力学性能,发现高结晶PP/GF的力学性能较普通PP/GF的提高15%~18%;同时考察了不同增容剂对高结晶PP/GF的力学性能的影响,均聚接枝物拉伸强度、弯曲强度较高,共聚接枝物的冲击强度较高;另外发现在PP/GF中加入山梨醇型α成核剂、芳酰胺类β成核剂后,两者对其性能有较大影响,使其力学性能降低40%以上。 相似文献
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研究了玻璃纤维(GF)和马来酸酐接枝聚丙烯(PP-g-MAH)对聚丙烯力学性能的影响。结果表明:随着GF与PP的质量比增加,玻璃纤维增强聚丙烯的拉伸强度增加,冲击强度总体呈下降趋势。当PP与GF的质量比为55∶45时,拉伸强度最高,达到45MPa。当PP与GF的质量比一定时,在玻璃纤维增强聚丙烯复合材料中添加增容剂马来酸酐接枝聚丙烯(PP-g-MAH),可使其拉伸强度得到很大的提高,但是冲击性能却下降。当PP与GF的质量比为75∶25时,随PP-g-MAH与PP/GF复合材料的质量比增加,其拉伸强度先增大后减小,其冲击性能总体呈下降趋势。当PP-g-MAH,PP和GF的质量比为15∶75∶25时,其综合性能最优,拉伸强度为50.5MPa,冲击强度为4.3kJ/m2。 相似文献
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采用熔体浸渍技术制备了长玻璃纤维母料(LGF/PP-g-MAH/PP)增强聚丙烯(PP)复合材料(LGF/PP)。通过双螺杆挤出机制备了同等配比的短玻纤增强聚丙烯(SGF/PP)复合材料。研究了LGF含量、环氧树脂(EP)和固化剂(2E4MZ)对LGF/PP复合材料的力学性能影响。结果表明:当LGF质量分数为35%~40%时,LGF/PP的综合力学性能最好,且明显优于同样组成的SGF/PP复合材料。EP和含固化剂(2E4MZ)的EP对LGF/PP复合材料的力学性能提高有一定的作用。SEM照片分析表明:EP的加入能改善玻纤与聚丙烯基体的界面粘接。 相似文献
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In this study, improvements in mechanical and thermal behavior of short glass fiber (GF) reinforced diglycidyl ether of bisphenol-A (DGEBA) based epoxy with hydroxyl terminated polybutadiene (HTPB) modification have been studied. A silane coupling agent (SCA) with a rubber reactive group was also used to improve the interfacial adhesion between glass fibers and an epoxy matrix. 10, 20, and 30 wt% GF reinforced composite specimens were prepared with and without silane coupling agent treatment of fibers and also HTPB modification of epoxy mixture. In the ruber modified specimens, hardener and HTPB were premixed and left at room temperature for 1 hr before epoxy addition. In order to observe the effects of short glass fiber reinforcement of epoxy matrix, silane treatment of fiber surfaces, and also rubber modification of epoxy on the mechanical behavior of specimens, tension and impact tests were performed. The fracture surfaces and thermal behavior of all specimens were examined by scanning electron microscope (SEM), and dynamic mechanical analysis (DMA), respectively. It can be concluded that increasing the short GF content increased the tensile and impact strengths of the specimens. Moreover, the surface treatment of GFs with SCA and HTPB modification of epoxy improved the mechanical properties because of the strong interaction between fibers, epoxy, and rubber. SEM studies showed that use of SCA improved interfacial bonding between the glass fibers and the epoxy matrix. Moreover, it was found that HTPB domains having relatively round shapes formed in the matrix. These rubber domains led to improved strength and toughness, due mainly to the “rubber toughening” effect in the brittle epoxy matrix. 相似文献
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Summary
The glass transition behavior of ternary blends of polypropylene (PP), polystyrene (PS) and styrene-ethylene-propylene-styrene
block copolymer (SEPS) was investigated. The blends were prepared by an internal mixer, and their dynamic mechanical properties
and morphology were measured. The blends showed phase inversion at around 75wt% PS composition. The glass transition temperature
(Tg) of the PP phase shifted to lower temperature as the PS contents were increased in PP/PS binary blends, probably due to the
mismatch of thermal expansion coefficients between two components. As the SEPS copolymer contents were increased, the Tg's of the PP phase in the blends increased. In particular, the large increase in Tg of the PP phase was observed in the PP/PS (25/75) blends where the phase inversion takes place.
Received: 2 February 1998/Revised version: 24 March 1998/Accepted: 13 April 1998 相似文献
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基于熔融共混法,分别采用双转子连续混炼挤出机和同向啮合双螺杆挤出机制备了20 %玻璃纤维增强聚丙烯(GFRPP)复合材料,并对制备出的GFRPP复合材料中玻璃纤维残存长度及其力学性能进行了相应表征,在此基础上探讨了具有不同混炼特性的混炼设备结构对GFRPP复合材料中玻璃纤维残存长度及其力学性能的影响。结果表明,GFRPP复合材料的力学性能随玻璃纤维残存长度的增加而明显提高;双转子连续混炼挤出机相对于同向啮合双螺杆挤出机更有利于保留长玻璃纤维,同时适当减弱双转子连续混炼挤出机的转子的分散混合能力,降低转子转速,有利于提高玻璃纤维的残存长度,制备出更高性能的GFRPP复合材料。 相似文献
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Performance of long glass fiber‐reinforced polypropylene composites at different injection temperature
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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 相似文献
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《Polymer-Plastics Technology and Engineering》2013,52(5):853-862
Abstract Natural fibers are potentially a high‐performance non‐abrasive reinforcing fiber source. In this study, pulp fibers [including bleached Kraft pulp (BKP) and thermomechanical pulp (TMP)], hemp, flax, and wood flour were used for reinforcing in polypropylene (PP) composite. The results show that pulp fibers, in particular, TMP‐reinforced PP has the highest tensile strength, possibly because pulp fibers were subjected to less severe shortening during compounding, compared to hemp and flax fiber bundles. Maleic‐anhydride grafted PP (MAPP) with high maleic anhydride groups and high molecular weight was more effective in improving strength properties of PP composite as a compatiblizer. Coupled with 10% glass fiber, 40% TMP reinforced PP had a tensile strength of 70 MPa and a specific tensile strength comparable to glass fiber reinforced PP. Thermomechanical pulp was more effective in reinforcing than BKP. X‐ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were used to aid in the analysis. Polypropylene with high impact strength was also used in compounding to improve the low‐impact strength prevalent in natural fiber‐reinforced PP from injection molding. 相似文献
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The effect of interfacial characteristics on the structure‐property relationships of ternary polymer alloys and blends comprising polypropylene (PP), ethylene‐vinyl alcohol copolymer (EVOH) and glass beads (GB) or fibers (GF) was investigated. The systems studied were based on a binary PP/EVOH immiscible blend, representing a blend of a semi‐crystalline apolar polymer with a semi‐crystalline highly polar copolymer. The ternary systems studied consisted of filler particles encapsulated by EVOH, with some of the minor EVOH component separately dispersed within the PP matrix. Modification of the interfacial properties was done using silane coupling agents for the EVOH/glass interface and compatibilization using a maleic anhydride grafted PP (MA‐g‐PP) for the PP/EVOH interface. Both glass fillers increased the dynamic modulus and decreased the damping of the neat polymers and of their binary blends, especially in the rubbery region. GF has a more profound effect on both the modulus and the damping. Glass surface treatments and compatibilization have only a marginal effect on the dynamic mechanical behavior of the ternary blends. Yet, compatibilization shifted the polymers' TgS to higher temperatures. Both glass fillers increased the elastic modulus of the binary blends, where GF performed better than GB as a reinforcing agent. GF slightly increased the strength of the binary blends while, GB reduced it. Both fillers reduced the ductility of the binary blends. The blends' mechanical properties were related to the morphology and their components' crystallinity. The compatibilizer increases both stiffness and strength and reduces deformability. 相似文献
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Blends of polypropylene (PP) and modified atactic polystyrene (PS) with good processability were studied for dyeable fine and superfine fibers. Acrylic acid and butyl acrylate monomers were added to PS by radical suspension copolymerization. The dispersion of the additives in the PP crystal was investigated. The rheology curves of the blends were similar to that of PP under the testing conditions. Fine and superfine PP filaments were processed from these blends, and they had practical mechanical properties. The dyeability of the fabrics from the fibers was studied. The increased amorphous content and the interface between PP and modified PS allowed the dyes to penetrate the fibers. These two effects helped to improve the color intensity. The color fastness was also improved by the presence of polar groups introduced by the modified PS components. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2360–2366, 2005 相似文献
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《国际聚合物材料杂志》2012,61(3-4):641-654
Abstract Rheological properties (melt flow index and melt stability), mechanical properties (tensile strength, flexural strength and impact) of polyamide (PA6) polypropylene (PP) blends were investigated. Influence of potential compatibilizors: 4,4′-diphenyhnethane carbodiimide (OCDI), 4,4′-diphenylmethane bismaleimide (BMI) and 2,2′-(1,4-pheaylene)-bisoxazoline (OX) on mechanical properties and thermostability of initial and glass reinforced polymer blends was also investigated too. We tried to study the structure of glass fiber reinforced composites by mercury intrusion porosimitry. The influence of compatibilizors on molecular weight of PA6 was studied by GPC, on chemical structure of blends was investigated by NMR and IR-spectroscopy. Addition of OCDI and OX (chain extenders) preserves the product formation as the react with the active and carbonyl groups of PA6. BMI has lower reactivity. Grafting of BMI to PP chains improves compatibility in PA6/PP blend and increases PP adhesion to glass fiber. 相似文献
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The dynamic rheological behavior was investigated for binary polypropylene (PP) - polyamide-6 (PA-6) and ternary PP-PA-6-glass fiber (GF) blends. The observed trends are related to the blend morphology and the partitioning of the GF within the three component blends. The dynamic and shear viscosity results show a good overlap for the PP homopolymer, within the shear rates studied. The addition of PA-6 and/or glass fibers to the PP causes significant deviations between the two rheological behaviors. This reflects the fibrillation of PA-6 and the orientation of glass fibers during shear rheometry, which reduce the blends' shear viscosity. The effect of PA-6 content on dynamic viscosity is less significant than for shear viscosity, owing to the absence of morphological structuring. The addition of PA-6 to PP increased the principal relaxation time of the binary blends. The addition of GF to these binary blends gave a further increase in the principal relaxation time. 相似文献