纳米SiO_2和PP-g-MAH对玻纤增强PP复合材料性能的影响

纤维和树脂之间的界面结合强度是决定复合材料性能的关键因素。通过实验研究在玻璃纤维表面涂覆经硅烷偶联剂KH550表面处理的纳米SiO_2以及在PP基体中加入PP-g-MAH对玻璃纤维增强聚丙烯复合材料的界面结合强度和力学性能的影响。结果表明,纳米SiO_2经KH550表面处理后可以降低其表面能,有利于其在纤维表面分散吸附;纤维表面涂覆纳米SiO_2及在PP中加入PP-g-MAH,有利于增强纤维和树脂之间的界面结合强度,复合材料的层间剪切强度提升了116.06%,拉伸强度提升了109.14%,弯曲强度提升了99.85%。     

连续GF增强PP层合片材破坏形式及层间剪切强度研究

采用热压工艺制备连续玻璃纤维(GF)增强聚丙烯(PP)混编纱层合片材及GF呈0°和0°/90°铺放的连续GF增强PP层合片材。通过对3种GF增强PP层合片材进行力学性能测试,结果表明,3种GF增强PP层合片材的拉伸、弯曲强度随着层数的增加基本呈现先升高后降低的趋势。由于层合片材的层间剪切强度存在差异,因而使得3种层合片材产生不同的拉伸及弯曲破坏形式。通过插入PP薄层及PP-g-MAH薄层可改善层合片材的层间剪切性能,但插入PP薄层会降低层合片材的拉伸及弯曲性能,而插入PP-g-MAH薄层有助于提高层合片材的拉伸及弯曲性能。     

PTT/PP共混物的性能研究

通过熔融共混制备了聚对苯二甲酸丙二酯/聚丙烯(PTT/PP=75/25)及其马来酸酐接枝PP(PP-g-MAH)增容共混物,研究了PTT/PP及其增容共混物的结晶性能、力学性能、流变性能和结晶形态。研究结果表明,PTT与PP共混能提高PP、PTT组分的结晶温度;对于增容共混物,随PP-g-MAH用量的增加,PP和PTT的结晶温度基本不变。加入PP使PTT拉伸强度降低,冲击强度提高;PP-g-MAH增容使共混物的拉伸和冲击强度都提高。增容共混物的熔体粘度明显降低,存在明显的剪切变稀现象,但熔体粘度与PP-g-MAH用量无关。在一定用量范围内,随PP-g-MAH用量的增加,PP分散相的尺寸变小。     

改性剂对连续玻璃纤维增强PP复合材料力学性能的影响

采用熔体挤出浸渍工艺制备连续合股无捻粗玻璃纤维(CUGF)增强聚丙烯(PP)复合材料。研究了以硅烷偶联剂γ-氨丙基三乙氧基硅烷(KH550)和PP接枝马来酸酐(PP-g-MAH)为界面改性剂对CUGF填充PP复合材料的界面相容性和PP力学性能的影响。结果表明,PP/PP-g-MAH/CUGF复合材料的力学性能明显优于PP/KH550/CUGF复合材料。在CUGF的质量分数为27%时,PP/PP-g-MAH/CUGF复合体系的拉伸强度比PP/KH550/CUGF复合体系的拉伸强度提高了47%,弯曲强度提高了64%,冲击强度提高了30%;黏弹行为显示,PP/PP-g-MAH/CUGF复合体系的弹性模量和黏性模量始终处于高位,说明分子链之间的相互作用增强,链段运动受到限制,PP分子链松弛时间增加;扫描电子显微镜照片显示,PP-g-MAH改善了PP树脂与玻璃纤维间的相容性,提高了界面黏结强度,使得拔出的CUGF表面黏附了一层树脂。     

多元复合高流动性聚丙烯的制备与性能

研究了滑石粉(Talc)及偶联剂用量、均聚聚丙烯(PP-H)与马来酸酐接枝物(PP-g-MAH)及PP-H对高流动性共聚聚丙烯(PP)性能的影响;比较了在填充20%Talc的共聚PP中分别添加PP-g-MAH和PP-H的复合体系力学性能及流变性能的变化规律。结果表明:钛酸酯偶联剂用量为1%(相对于Talc)时,所得Talc填充共聚PP综合性能最佳;当Talc用量大于10%时,共聚PP/Talc复合材料的拉伸强度、冲击强度、弯曲强度、熔体流动速率随Talc含量的增加而逐渐下降,弯曲模量则逐渐提高;PP-g-MAH对高流动性共聚PP的拉伸强度增强效果明显优于PP-H,PP-H则使共聚PP的熔体流动性明显下降。     

洋麻纤维的表面改性及其在聚丙烯基复合材料中的应用

采用碱处理、偶联剂处理以及碱–偶联剂复合处理对洋麻纤维进行表面改性,然后将其与聚丙烯(PP)纤维复合,采用非织造–模压工艺制备了PP/洋麻纤维复合材料。研究了上述3种表面改性方法对洋麻纤维强度及其复合材料弯曲与剪切性能的影响,并采用扫描电子显微镜(SEM)研究了洋麻纤维表面改性前后的形貌变化及其与PP基体之间的界面结合状况。结果表明,表面改性后洋麻纤维的拉伸强度均降低,但复合材料的弯曲强度及层间剪切强度均提高,表明这3种改性方法均提高了洋麻纤维与PP之间的界面结合强度;碱处理可去除纤维表面的果胶成分,使纤维束变得松散,使复合材料的弯曲强度及层间剪切强度分别较未表面改性时提高了21%和169%,但弯曲弹性模量降低了21%;偶联剂处理则使复合材料的弯曲强度,弯曲弹性模量和层间剪切强度较未表面改性时提高了23%,7%和160%;碱–偶联剂复合处理兼顾了碱处理和偶联剂处理的优点,使复合材料弯曲强度、弯曲弹性模量和层间剪切强度分别较未表面改性时提高了26%,18%和572%,综合性能最佳。SEM结果表明,碱–偶联剂复合处理后,复合材料中纤维与树脂之间的界面结合较好。     

用PP—g—MAH改进PP／GF带材性能的研究

用红外光谱法表征了接枝物的存在,考察了不同马来酸酐(MAH)用量和加工设备对接枝率的影响,并将接技物加入到聚丙烯/玻璃纤维(PP/GF)体系中挤出带材。通过测试,发现PP接枝物的加入提高了带材的弯曲强度,表明PP-g-MAH提高了相界面的作用力。     

PP-g-MAH增容PP／PA66共混物的形态结构和性能

用固相接枝法制备了马来酸酐接校改性聚丙烯(PP-g-MAH)，研究了PP-g-PMAH增容PP／PA66共混物的形态结构和性能。结果表明，未甩PP-g-MAH增容的PP／PA66共混物是热力学不相容的海岛型两相结构，而用PP-g-MAH增容的PP／PA66共混物虽是两相结构,但分散相粒子尺寸大大减小,PP-g-FMAH对PP／PA66共混物实现了反应性增容。与不合PP．rMAH的PP／PA66共混物相比，PP-g-MAH增容的PP／PA66共混物的拉伸强度提高约10MPa，弯曲强度提高约10MPa,弯曲模量增加10％,缺口冲击强度和伸长率保持不变。     

PP-g-MAH对玻璃纤维增强PP的影响

研究了聚丙烯接枝马来酸酐(PP-g-MAH)和剪切场强度等对玻璃纤维增强聚丙烯(GFRPP)性能的影响。加入PP-g-MAH后,GFRPP的拉伸强度持续增加,最大达82.5 MPa;弯曲性能大幅度提高;缺口冲击强度明显增大,最大达160.3 J/m;热变形温度基本维持不变。PP-g-MAH的加入可改善玻璃纤维与聚丙烯间的界面作用,从而有利于提高GFRPP的性能。在极高剪切场强度的条件下,GFRPP的力学性能和热性能有所下降。     

聚丙烯管材外增强试验研究

对聚丙烯(PP)管材用玻璃纤维增强塑料(GFRP)增强的PP/GFRP复合管进行了层间剪切强度测试和瞬时水压爆破试验,研究了PP管材的不同表面处理方法与粘结剂配方对PP/GFRP复合管层间剪切强度和爆破强度的影响。试验结果表明,经SH表面处理剂处理并使用SW粘结剂的PP/GFRP复合管具有显著的增强效果。且这种处理方法无污染、价廉,工程上易于实施。     

MAH—g—PP孚L液对PP／GF复合材料界面的影响

利用自制的MAH—g—PP乳液和KH-550溶液组合进行玻纤的表面处理。考察了MAH—g—PP乳液和KH-550溶液处理对PP／GF界面粘结的影响,研究了MAH—g—PP乳液处理玻纤表面的适宜温度和时间,探讨了MAH—g—PP乳液对PP／GF的偶联机理。结果表面：玻纤表面经MAH—g—PP乳液和KH-550溶液处理后,在PP／GF界面上形成了牢固的化学键连接,出现了明显的横晶层;MAH—g—PP乳液处理玻纤表面的适宜温度和时间为105℃、1h;MAH—g—PP乳液对PP／GF的偶联机理为乳液中的羧基与玻纤表面KH-550的氨基发生化学键合。     

长玻纤增强聚丙烯复合材料的研究

研究了长玻璃纤维/PP复合材料的力学性能和纤维在基体中的分布状况。结果表明：长玻纤在基体中呈现三维空间交叉分布,这种结构大幅度提高了复合材料的拉伸强度、冲击强度、硬度及软化点温度；玻纤的长度和用量对三维交叉结构的形成有很大影响；偶联剂KH-550处理玻纤表面后,材料的力学性能提高不大。     

Chemical coupling of polypropylene systems containing nonglass fillers

Maleic anhydride (MAH) modified polypropylene (PP) was demonstrated to be a chemical coupling agent in filled PP compounds. Improved properties were shown for talc and wollastonite filled PP compounds with MAH modified PP as a coupling agent. Partial replacement of glass fiber with wollastonite showed no reduction in properties.     

Influence of the Film Former on Fibre-Matrix Adhesion and Mechanical Properties of Glass-Fibre Reinforced Thermoplastics

The film former is in mass percentage the main component in most glass fibre sizes. Its influence on the fibre-matrix adhesion and the compound properties is studied in two thermoplastic matrices, i.e. polypropylene (PP) and rubber-modified styrene-co-maleic anhydride. The composition of the size is varied by changing the chemical nature and molecular mass of the film former and by leaving out the silane. The size's morphology on the glass fibres is studied with scanning electron microscopy and X-ray photoelectron spectroscopy. The effect on fibre-matrix adhesion is inferred from 0° bending and interlaminar shear strength measurements of unidirectional, continuous fibre reinforced composites. The possible effect of the film former on matrix crystallinity in PP is studied with differential scanning calorimetry and polarized-light microscopy. The same sizes are also tested in injection moulded, short fibre reinforced compounds by measuring their mechanical properties. In addition, the diffusion of the size into the matrix is studied by confocal scanning laser microscopy. The main conclusion of this study is that the film former plays a crucial role in the level of fibre-matrix adhesion because it does not diffuse away from the fibre-matrix interface into the matrix. Its effect may be larger than that of the silane. In addition, most mechanical properties of short fibre reinforced compounds improve with increasing fibre-matrix adhesion.     

聚丙烯/马来酸酐接枝聚丙烯/超细云母的界面增容及其断面形态研究

:针对 PP/云母相界面缺乏亲和力 ,云母对 PP力学性能改善不明显的缺陷 ,采用偶联剂KH- 570与 PP- g- MAH并用的技术对超细云母进行表面处理并与 PP共混增容。结果表明 ,云母能同时有效提高 PP的强度、模量、硬度和冲击强度。其中 ,由于 PP- g- MAH导致的界面强度提高和界面层厚度增加 ,使 KH- 570与 PP- g- MAH并用的 PP/PP- g- MAH/云母 - 4#材料比单用 KH- 570的PP/云母 - 4# 材料的改性效果更加明显。同时发现 ,云母对 PP的结晶过程具有较明显的成核作用 ,使改性 PP的结晶温度和熔融温度提高     

反应性相容剂的制备及其在PP/玻璃纤维复合材料中的应用

以马来酸酐(MAH)为接枝单体、丙烯酸-2-羟乙酯为共聚单体,利用熔融接枝技术对聚丙烯(PP)进行改性;以MAH/丙烯酸-2-羟乙酯熔融接枝改性PP为相容剂,研究相容剂对PP/玻璃纤维复合材料结构和性能的影响。结果表明:与未接枝PP相比,熔融接枝PP分子上接枝了MAH和—OH基团,而且熔融接枝反应对PP的熔点和热稳定性具有明显影响。另外,随着接枝PP含量的增加,PP/玻璃纤维复合材料的力学性能明显改善。当接枝PP含量为15%时,复合材料的拉伸强度提高了32%,冲击强度提高了13%,表明采用熔融共接枝工艺制备的PP具有优良的增容、偶联和分散效果。     

PP／PP—g—AA／云母复合体系结晶行为的研究

用示差扫描量热分析仪（DSC）、广角X射线（WAXD）的方法研究了PP/PP-g-AA（聚丙烯接枝丙烯酸）/云母复合体系的结晶行为,结果表明：云母、PP-g-AA对聚丙烯具有成核作用,而且云母的用量及PP-g-AA的用量及接枝率对聚丙烯的结晶性能都有影响。     

Preparation and characterization of high melt strength polypropylene with long chain branched structure by the reactive extrusion process

The reactive extrusion of maleic anhydride grafted polypropylene (PP‐g‐MAH) with ethylenediamine (EDA) as coupling agent is carried out in a corotating twin‐screw extruder to produce long chain branched polypropylene (LCBPP). Part of PP‐g‐MAH is replaced by maleic anhydride grafted high‐density polyethylene (HDPE‐g‐MAH) or linear low‐density polyethylene (LLDPE‐g‐MAH) to obtain hybrid long chain branched (LCB) polyolefins. Compared with the PP‐g‐MAH, PE‐g‐MAH, and their blends, the LCB polyolefins exhibit excellent dynamic shear and transient extensional rheological characteristics such as increased dynamic modulus, higher low‐frequency complex viscosity, broader relaxation spectra, significantly enhanced melt strength and strain‐hardening behaviors. The LCB polyolefins also have higher tensile strength, tensile modulus, impact strength and lower elongation at break than their blends. Furthermore, supercritical carbon dioxide (scCO₂) is constructively introduced in the reactive extrusion process. In the presence of scCO₂, the motor current of the twin extruder is decreased and LCB polyolefins with lower melt flow rate (MFR), higher complex viscosity and increased tensile strength and modulus can be obtained. This indicates that the application of scCO₂ can reduce the viscosity of melt in extruder, enhance the diffusion of reactive species, and then facilitate the long chain branching reaction between anhydride group and primary amine group. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Faser-Matrix-Haftung in Kunststoffverbunden aus thermoplastischer Matrix und Flachs, 2. Die anwendung von funktionalisiertem polypropylen

Adhesion of flax fibres to a polypropylene matrix in flax/PP composites was improved by pretreating the fibres with polypropylenes grafted with maleic anhydride (MAH). Prior to composite preparation, the flax fibres were loaded with the coupling agent. Shear strength and tear strength were improved by 100% and 25%, respectively. They depend on grafting degree and average molar mass of the PP-MAH graft copolymers. Comparable results were achieved by embedding untreated flax fibres in a PP matrix modified with MAH.