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 共查询到19条相似文献,搜索用时 125 毫秒
1.
辐射增强PP/BR共混体系的力学性能   总被引:5,自引:0,他引:5  
研究了在多官能团单体-三烯丙基异氰酸酯存在下,共混体系聚丙烯/1.4-聚丁二烯橡胶的辐射效应,用DSC,动态粘弹谱对其进行表征。结果显示,三烯丙基异氰酸酯主要分布于聚丙烯/1.4-聚丁二烯橡胶共混物的界面自高能射线作用下,被引发参与界面反应,从而改善了共混体系的相容性,增强也界面粘接,提高了共混物的力学性能。  相似文献   

2.
聚丙烯/聚对苯二甲酸乙二酯共混自增强材料的研究   总被引:5,自引:0,他引:5  
聚丙烯/聚对苯二甲酸乙二酯共混自增强材料的研究陈鸣才,黄玉惠,赵树录,廖兵,林果,丛广民(中国科学院广州化学研究所广州510650)关键词聚丙烯,聚对苯二甲酸乙二酯,高分子共混物,自增强材料聚对苯二甲酸乙二酯(PET)具有良好的成纤性和透明性,但收缩...  相似文献   

3.
利用自行设计制造的剪切拉伸双向复合应力场挤管装置生产出了双向自增强的无规共聚聚丙烯(PP-R C180)管材,研究分析了该双向应力场的剪切诱导效应对PP-R C180管材的结晶熔融、取向和拉伸强度的影响.结果表明,剪切拉伸双向复合应力场的引入所带来的剪切诱导效应促进了PP-R C180分子有序性的增加,使PP-R C180体系分子更容易形成分别沿管材周向和轴向方向的取向,因而保持甚至提高了耐热性与结晶速率,降低了结晶度,改变了PP-R C180的结晶结构与形态,诱导出了全新的β晶,进而改善了管材的强度性能.与常规管材相比,自增强管材在保持其熔点不降低的前提下,使结晶度从常规管材的44.96%降至40.03%,降低了4.93%;轴向强度从常规管材的23.35 MPa最高增强到25.49 MPa,提高了9.2%;周向强度从常规管材的22.71 MPa最高增强到26.54 MPa,提高了16.9%,且增强之后管材的周向强度已经高于了轴向强度,更优化地配置了聚合物材料的性能,更充分地满足了受内压管材使用的现实需求.  相似文献   

4.
硅灰石填充聚丙烯复合材料性能的研究   总被引:3,自引:1,他引:2  
本文研究了硅灰石填充聚丙烯(含乙烯22%)复合材料的热学、广角X-射线衍射和动态力学性质。复合材料中β晶含量随硅灰石含量增高而增加。试样的熔融及结晶行为表明,所有硅灰石填充试样均含有α和β两种晶型,4个结晶熔融转变;而未填充试样只有a晶型,2个结晶熔化转变。在DSC曲线上,β晶在升温过程中转变成α晶型。硅灰石填料对聚丙烯动态力学性能的影响表明,硅灰石起到了增强剂和β晶成核剂的双重作用,填料硅灰石已进入聚丙烯的结晶相。  相似文献   

5.
界面改性对玻纤增强聚丙烯弯曲强度的影响   总被引:4,自引:0,他引:4  
为了提高玻纤增强聚丙烯(PP)的界面粘结,分别用B301或硅烷偶联剂对玻纤表面进行了处理,用过氧化物和顺丁烯二酸酐对PP进行了改性。经处理和改性后,PP/GF复合材料的弯曲强度有明显提高,对玻纤增强聚丙烯的界面结构也作了探讨。  相似文献   

6.
β晶型聚丙烯的力学性能与结晶行为研究   总被引:35,自引:0,他引:35  
研究了β晶型成核剂(酰胺化合物)用量对聚丙烯力学性能的影响,并对β晶型聚丙烯进行了偏光显微镜观察,DSC和广角X射线衍射分析。结果表明:添加β晶型成核剂后,聚丙烯的球晶细密化,α晶型向β晶型转变,韧性增强。  相似文献   

7.
长玻纤增强聚丙烯复合材料被称为热塑性玻璃钢,由于具有较好的力学性能、成型工艺容易控制、易回收利用等特点,已经成为传统玻璃钢的替代产品。本文以聚丙烯作为基体,长玻纤母料作为增强相,加入相容剂以及其它助剂,制备可回收利用、满足环保要求的绿色复合材料,并对其拉伸、弯曲性能进行测试,进而得出长玻纤母料对聚丙烯的增强作用。研究结果表明:长玻纤母料与聚丙烯具有很好的相容性,能够错落有致地分布于聚丙烯基体中,达到很好的增强效果。  相似文献   

8.
聚丙烯/尼龙6/聚丙烯接枝物原位复合材料的形态与力学性能———共混过程对体系的影响黎学东陈鸣才黄玉惠丛广民(中国科学院广州化学研究所广州510650)关键词原位复合材料,成纤,相容性原位成纤复合材料是指在加工过程中增强相在基体中就地形成微纤,不...  相似文献   

9.
增容剂对聚丙烯/粘土纳米复合材料热分解动力学的影响   总被引:12,自引:0,他引:12  
采用三单体固相接枝聚丙烯作为增容剂制备了聚丙烯粘土纳米复合材料.通过XRD和TEM表征了其纳米结构.利用动态TGA方法研究了聚丙烯和纳米复合材料的热稳定性.分别采用Flynn Wall Ozawa和Kissinger法研究了聚丙烯及其纳米复合材料的热分解动力学.结果都表明,蒙脱土的加入明显提高了聚丙烯的起始热分解温度,纳米复合材料热失重10%时的温度比聚丙烯提高40K左右;纳米复合材料的热分解温度区间明显比聚丙烯的窄;纳米复合材料热分解表观活化能明显增大,与聚丙烯相比提高50%以上.  相似文献   

10.
竹纤维具有密度低、强度高、价格低和可再生等优点,是工程结构材料中的理想增强材料。以竹纤维增强聚丙烯是目前制备高性能聚丙烯复合材料的研究热点,也是可持续发展的重要方向之一。为得到高性能的复合材料,需要对竹纤维和聚丙烯基体界面进行处理。本文综述了改善竹纤维与聚丙烯基体界面相容性的三种方法,包括竹纤维的表面改性、聚丙烯基体的改性和添加第三组分,指出了三种方法的优缺点,并展望了提高竹纤维/聚丙烯复合材料界面相容性的研究方向。  相似文献   

11.
HDPE/PP共混物在振动剪切作用下的力学性能与形态控制   总被引:4,自引:0,他引:4  
采用高剪切引起的相容与振动剪切保压方法控制共混物的形态,结果表明,当共混体系中HDPE/PP为92/8的试样拉伸强度为97.1MPa,而80/20试样的缺口冲击强度为45.5kj/m^2,较静态试样分别提高4.3倍和9.5倍。采用振动剪切注射技术可以针对某一组分获得高强度、高韧性的HDPE/PP共混制件。  相似文献   

12.
常压动态保压注塑自增强高密度聚乙烯的结构与性能   总被引:6,自引:0,他引:6  
研究了常压动态保压注塑自增强高密度聚乙烯的结构和力学性能的关系,自增强高密度聚乙烯的抗张强度和杨氏模量分别从原来的23MPa和1.0GPa提高到93MPa和5.0GPa。DSC、TEM和X射线衍射研究结果表明:力学性能的显著改善主要归因于串晶的产生、高分子链沿流动方向的轴取向和结构更加完善的球晶的生成。和高压保压法相比,本法具有现实的工业应用前景。  相似文献   

13.
Drawing behavior, flow drawing, and neck drawing, was studied for isotacticpolypropylene fibers in CO2 laser drawing system, and the fiber structure and the mechanical properties of drawn fibers were analyzed. For a certain laser power, flow drawing of polypropylene (PP) was possible up to draw ratio (DR) 19.5. Though the drawing stress was very low, the flow‐drawn PP fiber exhibited oriented crystal structure and improved mechanical properties. On the other hand, neck‐drawing was accomplished from DR 4 to 12, with significant increase in drawing stress that enhanced the development of fiber structure and mechanical properties. Unlike PET, the drawing stress depends not only on the DR, but on irradiated laser power also. The 10–12 times neck‐drawn fibers were highly fibrillated. The fibers having tensile strength 910 MPa, initial modulus 11 GPa, and dynamic modulus 14 GPa were obtained by single‐step laser drawing system. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 398–408, 2006  相似文献   

14.
在常规注射过程中 ,难以获得超高性能的共混体系注射制件 ,已有的研究表明 ,采用高剪切注射 ,可以抬高共混体系的最低临界相容温度曲线 (LCST)的位置 ,增加相容性 .当熔体进入模具后 ,冷却的同时相容性下降 ,开始相分离 ,相分离程度发展到某一程度即可获得高性能的制件 .对于高密度聚乙烯 (HDPE)、聚丙烯 (PP)两组分均为结晶型聚合物的共混体系 ,由于其相形态与结晶形态相互制约、竞争 ,微相分离程度难以控制 ,因此对其液 液相形态与结晶过程的控制是获得共混物最终形态与性能的关键 .采用振动保压注射成型技术不仅对HDPE、PP各自力学性能有明显的自增强作用 ,而且对HDPE/PP共混体系的力学性能也有十分明显的改善 .DSC、WAXD、SEM结果表明共混体系拉伸强度的提高主要取决于试样中串晶数量和大分子链的定向程度 ,而冲击强度则主要取决于两组分微观的相分离程度 .研究结果表明 ,HDPE/PP含量为 92 / 8的试样拉伸强度为 97 1MPa,80 / 2 0试样的缺口冲击强度为 4 5 5kJ/m2 ,较静态试样分别提高 4 3倍和 9 5倍 .采用振动填充注射技术针对某一组分可以获得高强度、高韧性的共混制件 .  相似文献   

15.
In this article, crystalline morphology and molecular orientation of isotactic polypropylene(i PP), random copolymerized polypropylene(co-PP) and ?-nucleating agent(?-NA) composites prepared by pressure vibration injection molding(PVIM) have been investigated via polarized light microscopy, scanning electron microscopy, wide-angle X-ray diffraction and differential scanning calorimetry. Results demonstrated that the interaction between co-PP and i PP molecular chains was beneficial for the mechanical improvement and the introduction of ?-NA further improved the toughness of i PP. In addition, after applying the pressure vibration injection molding(PVIM) technology, the shear layer thickness increased remarkably and the tensile strength improved consequently. Thus, the strength and toughness of i PP/co-PP/?-NA composites prepared by PVIM were simultaneously improved compared to those of the pure i PP prepared by conventional injection molding(CIM): the impact toughness was increased by five times and tensile strength was increased by 9 MPa. This work provided a new method to further enhance the properties of i PP/co-PP composites through dynamic processing strategy.  相似文献   

16.
Microfibrillated cellulose (MFC)-reinforced polypropylene (PP) was prepared via two engineering approaches: disintegration of the pulp by a bead mill followed by a melt-compounding process with PP (B-MFC-reinforced PP); and disintegration of the pulp mixed with PP by a twin screw extruder followed by a melt-compounding process (T-MFC-reinforced PP). The effects that the engineering process and the microfibrillation of the pulp had upon the dispersion and mechanical properties were investigated through tensile tests, rheological analysis and X-ray computed tomography. The bead-milling method enabled a uniform microfibrillation of the pulp to under 100 nm, which corresponded to a surface area of 133–146 m2/g for the pulp, found by the Brunauer–Emmett–Teller (BET) analysis. The T-MFC-reinforced PP with 30 wt% MFC content exhibited a tensile modulus of 5.3 GPa and a strength of 85 MPa, whereas the B-MFC-reinforced PP composites with the same content of MFC exhibited values of 4.1 GPa and 59.6 MPa, respectively. Rheological analysis revealed that the complex viscosity and storage modulus at 170 °C of T-MFC-reinforced PP with 30 wt% MFC content are 5–7 and 5–8 times higher than that of B-MFC-reinforced PP, respectively. This indicated that T-MFC was more dispersed in the PP than B-MFC. Therefore, T-MFC produced a more rigid interconnected network in the matrix during the melting state than B-MFC.  相似文献   

17.
低密度聚乙烯在振动填充注射过程中的自增强   总被引:8,自引:1,他引:7  
聚烯烃自增强的研究极具应用前景,正逐渐成为人们关注的热点.其目的是利用现有通用级聚烯烃材料,通过特殊的加工方法,挖掘材料内在潜力,开发力学性能可与工程塑料相媲美的聚烯烃制品.我们的研究表明,利用振动填充注射成型技术,在低压下就能实现普通高密度聚乙烯(...  相似文献   

18.
The crystallization kinetics of polypropylene (PP), polyamide (PA66), and poly(ethylene terephthalate) (PET) were studied, using a pressure dilatometer (to 200 MPa) to follow the volume changes associated with the crystallization process. The commonly used Avrami equation fitted the isothermal/isobaric crystallization data of PP and PA66 well. The Avrami exponent n was between 1.3 and 1.7, independent of crystallization pressure and temperature. Lines of constant Avrami rate parameter Z in the P-T plane were essentially parallel to the pressure dependence of the melting points and crystallization temperatures. However, the Avrami equation was not suitable for PET. The Malkin, Dietz, and Kim equations provided better fits. The crystallization half-time of PET increased with pressure at constant supercooling, in contrast to PP and PA66, for which it remained essentially unchanged. X-ray diffraction, differential scanning calorimetry, and pressure dilatometry were used to study the effect of formation pressure on the crystal structure, the melting point, and the density of products which were crystallized for short times (minutes) at various temperatures and pressures. No new crystal structures were found for PA66 and PET, but a mixture of monoclinic and triclinic crystals existed in PP above a formation pressure of 50 MPa. The melting points increased with formation pressure for PET, but remained unchanged for PP and PA66. Density at ambient conditions decreased with formation pressure for PP, but increased for PET and PA66. © 1994 John Wiley & Sons, Inc.  相似文献   

19.
徐亮  戴婷  陈涛  匡莉 《广州化学》2021,(2):75-80
采用DOE实验设计方法,对聚丙烯(PP)材料焊接工艺进行了研究,确定了影响PP材料焊接强度的关键因素是气压夹紧力、焊接功率和样品厚度。通过全因子正交试验,对焊接强度和焊接工艺参数进行量化分析,通过优化器结果确定对共聚PP(牌号M60RHC)为原材料,样品厚度为2 mm,控制气压夹紧力为0.3 MPa,焊接功率控制在40 W,得到PP材料的最佳焊接工艺,降低了实验的次数,在该最大工艺条件下,焊接强度达到19.475 MPa。这将有助于其他原材料体系进行高效激光焊接工艺的筛选。  相似文献   

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