共查询到19条相似文献,搜索用时 734 毫秒
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采用涂覆层压法制备了3层和5层结构的PVC/PVA复合薄片。探究了不同浓度、聚合度、醇解度的PVA水溶液对薄片的阻隔性能的影响,利用扫描电子显微镜(SEM)观察了不同型号、浓度的复合薄片的微观形态。结果表明:复合薄片的力学性能随着PVA溶液浓度的提高而提高;PVA溶液浓度、聚合度、醇解度的提高均能降低PVC/PVA复合薄片的透湿率;采用浓度较高或醇解度较高的PVA溶液制备的复合薄片可以更好的保持PVC/PVA复合薄片的层状结构。实验证明:用浓度为10%的PVA溶液涂覆具有PVC/PVA/PVC/PVA/PVC结构的复合薄片的阻隔性能较好。 相似文献
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复合拉伸力场挤出HDPE片材的力学性能 总被引:1,自引:1,他引:0
利用收敛-发散口模挤出制备了高密度聚乙烯(HDPE)片材,研究了挤出温度对片材力学性能的影响.结果表明:在复合拉伸力场作用下,熔态挤出(140℃)片材的纵、横向屈服拉伸强度分别为28.3,27.0MPa,固态挤出(112℃)片材的纵、横向屈服拉伸强度分别为181.4,51.3 MPa,纵、横向屈服拉伸强度分别增加了540%和90%.与固态挤出相比,熔态挤出片材纵、横向断裂伸长率分别增加了760%和124%.扫描电子显微镜显示,熔态挤出HDPE片材由球晶结构构成;固态挤出片材由大量垂直于挤出方向规整排列的片晶组成,并有少量的串晶生成,片晶厚度增加,这种结构有利于改善制品的双向力学性能. 相似文献
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采用自行设计的多级拉伸设备制备了聚丙烯/有机改性蒙脱土纳米复合材料,并对复合材料的热稳定性,阻隔性能和流变学性能进行了研究。实验结果表明:多级拉伸挤出技术不仅能有效的使填料分散,并且能使有机改性的蒙脱土在基体中沿流动方向取向,从而在一定程度上提高复合材料的性能。 相似文献
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以片状云母粉为阻隔改性剂,与高密度聚乙烯(PE–HD)熔融共混,以改善其对汽油的阻隔性,考察云母粉形貌、含量等因素对PE–HD/云母粉复合材料阻隔性、熔体流动性以及力学性能的影响。结果表明,云母粉可显著提高复合材料对汽油的阻隔性,但熔体流动速率(MFR)与断裂伸长率降幅明显,高径厚比的云母粉对复合材料的汽油阻隔性提升更为显著,但径厚比过大不利于阻隔性的进一步提升,并会导致材料MFR和断裂伸长率进一步下降;当云母粉含量开始增加时,复合材料的汽油阻隔性明显提升,拉伸强度与缺口冲击强度上升,而MFR和断裂伸长率下降,当裂纹发展方向垂直于云母片面积方向时,缺口冲击强度提高更为显著;随着云母粉含量继续增加,复合材料的汽油阻隔性趋于稳定,拉伸强度与缺口冲击强度却明显下降。当径厚比为180的云母粉质量分数为30%时,复合材料具有最佳的综合性能,其汽油浸泡后的拉伸强度保持率显著高于纯PE–HD。 相似文献
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通过溶液浇铸法制备了纤维素纳米纤丝(CNFs)/聚乙烯醇(PVA)复合材料,利用TG、DSC、DMA等方法考察了CNFs对PVA热性能与力学性能的影响。结果表明:CNFs的加入提高了PVA的结晶度与熔点,但随着CNFs含量的增加,由于CNFs与PVA之间存在较强的氢键作用,限制了PVA分子链的运动,使得PVA的熔点与结晶度略有下降;CNFs的加入使得PVA的玻璃化转变温度、拉伸强度与弹性模量提高,添加2%CNFs的PVA复合材料的拉伸强度与弹性模量均达到最大值,分别较纯PVA提升了28.9%与14.1%。 相似文献
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This paper studies the phenomenon of fiber alignment during the extrusion process. The fiber alignment is largely dependent on shapes of dies and the compression as well as the shear force generated in the extruder. The fiber alignment orientation, of course, would lead to direction dependency of the tensile properties of fiber-reinforced cement (FRC) extrudates. Such a dependency has been investigated in present study. It is found that when fiber volume ratio is small, say 1% of the glass fiber, the majority of the fiber can be aligned in the extrusion direction. As a result, the tensile strength of the thin plate along the extrusion direction is much higher than that along the transverse direction. When the total fiber volume ratio is increased to 2% or 4%, the fiber volume along the transverse direction is largely increased although the percentage of the fiber aligned along the extrusion direction is still higher. Thus, the tensile strength at a transverse direction can be significantly enhanced. In fact, the tensile strength of the samples along the transverse direction is almost the same as that along the extrusion direction when the fiber volume ratio reaches 2%. Furthermore, the strength of the sample at the extrusion direction does not increase proportionally to the fiber volume ratio. For the comparison purpose, plain sheets without any fibers have been prepared by both casting and extrusion. Mechanical properties of the sheets have also been tested and the test results show that extrusion process and fiber addition do have effects on enhancing the tensile properties. Polymer coating on the surface of the samples has also been used to improve the tensile properties of the extrudates with low fiber volume ratio, which shows some promising results. 相似文献
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Square sheets of extrusion grade polystyrene (PS) were biaxially stretched using a laboratory biaxial stretcher. The effects of process parameters such as stretch ratio, drawing sequence, drawing speed, and temperature were studied. Birefringence, mechanical properties, and thermal shrinkage of the stretched sheets were the focus of this study. A high orientation was achieved at high stretch ratio, and orientations from uniaxial to equi‐biaxial were obtained by controlling the relative magnitude of stretch ratio in machine (MD) and transverse (TD) directions. Stretching increased tensile strength and elongation at break significantly, which indicated an improvement in the toughness of the oriented PS sheets. Those properties were correlated with biaxial orientation factors: a rapid increase was observed for both tensile strength and elongation at break for birefringence levels above ?0.005, and below, a plateau was observed. The shrinkage strain and stress were found to correlate well with the biaxial orientation factors. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 487–496, 2003 相似文献
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《塑料、橡胶和复合材料》2013,42(9):367-373
AbstractA highly filled PVA/talc composite was prepared through our invented thermal processing technology without using any coupling agent or compatibiliser. The results showed that compared with neat PVA, the melt temperature of the composite decreased and the degradation temperature increased, providing a big temperature window for thermal processing of PVA/talc composite. The composite melt exhibited shear thinning behaviour while its viscosity increased with increasing talc, still satisfied the requirement of thermal processing. The morphology analysis confirmed that talc was well dispersed in PVA, improving heat deflection temperature (HDT), tensile strength and modulus of PVA. When talc was 50 wt-%, the HDT, tensile strength and modulus of the composite were 115°C, 48 MPa, 1·23 GPa respectively, increased by 92, 16 and 150%, compared with PVA, and the elongation at break was 100% of the composite, confirming that the high filled PVA/talc composite was a novel PVA based material with excellent thermal and mechanical properties. 相似文献
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将纳米TiO_2、稻壳粉、聚氯乙烯(PVC)和稳定剂等按一定比例混合,用挤出成型法制备PVC/稻壳粉木塑复合材料。考察纳米TiO_2添加量对PVC/稻壳粉木塑复合材料性能的影响。实验结果表明,随着纳米TiO_2含量的增加,木塑复合材料的力学性能、防水性能和热稳定性呈现先增加后降低的趋势,但木塑复合材料的表面颜色却随着纳米TiO_2含量的增加而逐渐变浅。当纳米TiO_2含量为1.00份时,木塑复合材料的综合性能最好,与未添加纳米TiO_2的木塑复合材料相比,其拉伸强度、冲击强度和弯曲强度分别提高了40.6%,62.2%和19.7%,8 d的吸水率从2.5%降低为1.6%,表面接触角从78.5°增加到82.1°,800℃时的残炭率从21.1%提高到29.5%。 相似文献
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Omdeo Kishorrao Gohatre Manoranjan Biswal Smita Mohanty Sanjay K Nayak 《Polymer International》2020,69(6):552-563
The present study deals with the development of composite materials utilizing recycled poly(vinyl chloride) (r‐PVC) recovered from waste electrical and electronic materials and waste fly ash obtained from thermal power plants. The effect of the incorporation of fly ash on the mechanical, thermal and morphological properties of the r‐PVC matrix was studied. The primary characterization of r‐PVC and fly ash was done employing FTIR, EDX, particle size analysis and XRD analysis. Subsequently, fly ash with a particle size of approximately 9.29 μm was incorporated within the r‐PVC matrix. Composite sheets were prepared using a melt blending process followed by compression moulding. The mechanical test revealed an increase in the tensile strength and elongation at break of the r‐PVC/fly ash composite up to 30 wt% loading of fly ash beyond which there was a decrease in the tensile strength. The impact strength, however, decreased with increasing fly ash content in the r‐PVC matrix. The morphological properties of the composites showed a good distribution of the filler within the recycled matrix. The thermal properties of r‐PVC also improved with the incorporation of fly ash which was revealed from DSC and TGA studies. The water absorption test showed an increase in water uptake with the addition of fly ash in the r‐PVC matrix. © 2020 Society of Chemical Industry 相似文献
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Plasticized polyvinyl chloride (PVC) films were prepared by melt compounding and compression molding using epoxidized cardanol (EC), a biobased plasticizer and its plasticization effect was compared with epoxidized soybean oil (ESBO) and dioctyl phthalate (DOP). The mechanical, migration, thermal, and barrier properties of the plasticized films were compared. The effect of replacing DOP with EC on the properties of PVC films was also investigated. The tensile strength, elongation at break, tensile modulus and impact strength values of PVC/EC films were higher in comparison to PVC/DOP and PVC/ESBO films at a fixed plasticizer loading of 40 wt.%. Also, the films prepared with a mixture of DOP + EC showed higher tensile strength and elongation at break compared to that of films prepared with only DOP. The PVC/EC films showed good thermal stability and reduced oxygen transmission rate (OTR) compared to PVC/DOP films. The addition of graphene and nanoclay in the PVC/plasticizer system exhibited an increase in oxygen transmission. However, the oxygen barrier property of nano filler incorporated PVC/EC films was better than PVC/DOP films. All the films showed negligible water vapor transmission rate (WVTR). 相似文献