纸浆细纤维化对纤维基聚氨酯合成的影响

利用物理检测、SEM观察、XPS检测等方法探究了打浆前后纤维基聚氨酯复合材料的物理指标、表面形态以及成键情况,分析了纸浆细纤维化对纤维基聚氨酯复合材料性能的影响。通过对纤维基聚氨酯复合材料的物理性能检测分析可知,当咪唑-TDI-PEG400聚氨酯预聚体乳液加入量为10%时,随着浆料打浆度的提升,复合材料的抗张指数、湿抗张指数、耐折度、撕裂指数逐渐升高。当浆料打浆度为55°SR时,复合材料的抗张指数、湿抗张指数、耐折度、撕裂指数分别为空白样品的1.06、9.75、1.12、1.12倍。通过SEM也可以观察到,打浆度越高,纤维间的膜状包裹以及纤维间的桥接也逐渐增加。最后通过XPS表征抄片表面价键结合状态,发现随着打浆度的提升,抄片表面的氨基甲酸酯键含量逐渐提高。在打浆度为75°SR时,氨基甲酸酯的含量为1.63%,为10°SR抄片的6.30倍。     

TEMPO氧化体系对废纸浆纤维的氧化改性

目的利用2,2,6,6-四甲基哌啶氧化物自由基(TEMPO)/NaClO/NaBr氧化体系改善废纸浆纤维成纸的性能。方法以废纸浆为原料,在碱性条件下采用TEMPO/NaClO/NaBr氧化体系对纤维进行选择性氧化,得到不同羧基含量的氧化废纸浆,通过纤维形态分析仪及化学分析法对纤维形态和羧基含量进行分析和测定;将氧化废纸浆、氧化废纸浆与原浆进行抄片和配抄,对手抄片的强度性能进行检测和分析;从经济效益出发,研究氧化体系中TEMPO及NaBr的循环使用次数对纸张强度性能的影响。结果随着NaClO用量的增加,废纸浆纤维的羧基含量增加;纤维长度、宽度和粗度有所降低;纸张抗张强度和环压强度增长较为明显;NaClO和NaBr循环使用2次后纸张的强度性能有所降低,但降低幅度不大。结论TEMPO氧化体系可用于废纸浆的氧化,改善废纸浆的性能。NaClO和NaBr的循环使用能够降低生产成本。     

麦饭石用于功能纸填料的实验研究

采用麦饭石超细粉为填料制备功能纸手抄片,通过光学显微镜、SEM和细菌菌落总数检测分析,研究了麦饭石超细粉掺加量和手抄片性能的关系。结果表明:手抄片的拉力、断裂长、挺度、撕裂度随麦饭石超细粉掺加量的增加而减小;50%和75%掺加量时手抄片的耐折度和吸水率都比10%掺加量的手抄片高,变化趋势是随掺加量增加先增大而后又减小;掺加了麦饭石的手抄片测试组菌落总数少于阳性对照组,且随着掺加量的增大,测试组菌落总数减少,制备的麦饭石功能纸具有一定的抑菌作用。     

硅烷偶联剂的水解工艺研究

通过测定硅烷偶联剂KH-550水解液的电导率及红外光谱,研究影响硅烷偶联剂水解稳定性的因素。结果表明,硅烷偶联剂KH-550的最佳水解工艺条件如下:乙醇与水的混合溶液为溶剂,采用正水解方式,KH-550、溶剂与水三者的质量比为1∶144∶16,水解液pH为2,水解时间为20 min。     

植物纤维增强PS木塑复合材料的性能研究

以木纤维、竹纤维和聚苯乙烯为主要原料,加入偶联剂、润滑剂、增塑剂等加工助剂,经挤出注塑制备聚苯乙烯/木纤维复合材料。研究了植物纤维种类和添加质量分数、偶联剂KH-550添加质量分数对PS木塑复合材料力学性能的影响。结果表明：木纤维和偶联剂的加入都使复合材料的力学性能呈先增大后减小的趋势。当木纤维添加质量分数为25%,偶联剂KH-550添加质量为木纤维添加质量的1.5%时,复合材料具有最大的拉伸强度、弯曲强度和断裂伸长率,分别为30.2MPa,86MPa和8.74%,缺口冲击强度随木纤维添加质量分数的增加而减小。木纤维和竹纤维填充的两种复合材料的拉伸强度、弯曲强度和冲击强度相差不大。     

硅烷偶联剂改性绢云母及其在天然橡胶中的应用

为了提高绢云母改性效果及工业应用价值,采用硅烷偶联剂KH-550对绢云母粉体进行改性,并对工艺条件进行研究;通过润湿接触角、水杨醛-乙醇显色、红外光谱、橡胶制品力学性能和扫描电镜等分析和表征KH-550对绢云母粉体的改性效果。结果表明,改性绢云母最适宜条件为KH-550质量分数为1.6%,温度100℃;改性后,KH-550以化学键合作用为主附着于绢云母表面;以改性绢云母作橡胶填料,能改善橡胶制品的力学性能,KH-550改性绢云母因其片状晶形和特殊表面性质适合作硫化橡胶的补强填料。     

中温淀粉酶改性玉米淀粉在纸板中的应用研究

目的 以酶改性玉米淀粉为施胶剂,对箱纸板和瓦楞纸板进行表面施胶,研究其对纸板物理性能的影响.方法 使用中温淀粉酶改性玉米淀粉,测试其粘度变化;然后将酶改性淀粉施胶于箱纸板和瓦楞纸板表面,测试箱纸板的挺度、环压强度、耐破度、耐折度、抗张强度以及瓦楞纸板的边压强度和耐破度,探索酶改性玉米淀粉对箱纸板和瓦楞纸板表面施胶的最佳用量.结果 使用2.5μL淀粉酶改性质量分数为10％的玉米淀粉后,将其施胶于箱纸板表面,此时箱纸板的物理性能最优.与空白样相比,箱纸板的横向挺度提高了380％,纵向挺度提高了464％,环压强度提高了53.2％,纵向抗张强度提高了10.6％,横向抗张强度提高了9.6％,箱纸板的耐破度变化不大,耐折度降低;经2μL淀粉酶改性质量分数为10％的玉米淀粉后,将其施胶于瓦楞纸板表面,其边压强度提升最多;与空白样相比,边压强度提高了45.5％.结论 酶改性玉米淀粉的制作工艺简单,为制备高性能纸板提供了参考依据.     

有机蒙脱土改性石蜡乳液对废纸纤维结构和性能的影响

采用逆转法,以有机蒙脱土(OMMT)复配乳化剂,制备了OMMT改性石蜡乳液,利用红外光谱、热重分析等手段分别对OMMT改性石蜡乳液的结构进行了表征,同时研究了OMMT改性石蜡乳液对废纸纤维施胶后的接触角和力学性能的影响。结果表明,加入质量分数1%的OMMT改性石蜡乳液,能更显著地提高施胶后的纸张的接触角,其耐水性、撕裂强度、拉伸强度、环压强度、耐破度等也得到明显的提高。扫描电镜对纸张纤维表面的研究表明,加入OMMT改性石蜡乳液后,纸张纤维表面孔洞较少,纤维的结合比较均匀,结构较致密。     

聚乙烯/杨木粉基木塑复合材料的性能研究

目的 研究硅烷偶联剂(KH-550)处理木粉以及微胶囊红磷(HP)阻燃对木塑复合材料(WPC)的性能影响.方法 以杨木粉、低密度聚乙烯(LDPE)、线性低密度聚乙烯(LLDPE)和HP为原料,采用二次共混造粒及注射模塑法,制备WPC,通过熔体流动速率(MFR)试验、拉伸试验、TGA谱图分析、Kissinger动力学分析和SEM显微观察研究WPC的性能.结果 采用KH-550处理木粉后,体系的MFR提高了0.01 g/min,拉伸时的最大位移提高了2.59 mm,HP的添加使WPC在分解5％和50％时的温度分别提高了18℃和54℃,KH-550和HP共改性的WPC在420～500℃(主要分解阶段)的表观活化能为153 kJ/mol.结论 采用KH-550处理杨木粉后,使体系的拉伸性能得到有效改善,在添加质量分数为10％的HP后,WPC的阻燃效果得到显著提高.     

偶联剂处理玻璃纤维改性聚酰亚胺摩擦磨损性能研究

采用不同硅烷偶联剂对玻璃纤维(GF)进行表面处理,制备了热塑性聚酰亚胺(TPI)复合材料,考察了纤维含量及粒径对复合材料摩擦学性能的影响,并利用SEM分析了磨损机理.研究表明:经表面处理的GF填充TPI复合材料的力学性能和摩擦磨损性能均有提高,以KH-550处理效果最好;随着GF含量的增大,KH550处理的TPI复合材料的磨损率逐渐增大,摩擦系数比纯TPI略有增大;复合材料的磨损率与摩擦系数随纤维粒径的减小而降低;SEM显示处理后的GF与基体之间形成了良好的界面,复合材料的磨损以粘着磨损与磨粒磨损为主.     

偶联剂处理对玻璃纤维/尼龙复合材料力学性能的影响

采用KH-550 和KH-570 两种不同的偶联剂处理玻璃纤维, 得到的玻璃纤维增强铸型(MC) 尼龙复合材料( GFRMCN) 的力学性能差别很大。经过KH-570 处理GFRMCN 力学性能降低, 而经过KH₂550 处理能有效提高其力学性能; KH₂550 质量分数与处理的玻璃纤维质量分数之间符合定量关系式, 含量为0. 2 %时, GFRMCN的弯曲强度提高了35 % , 弯曲模量提高了72 % , 拉伸强度提高了46 % , 弹性模量提高了88 % , 冲击强度提高了41 %。KH-550 偶联剂在玻璃纤维与尼龙基体之间形成良好界面结合, 达到增强效果; 而未经处理的玻璃纤维断裂时从基体中拔出, 玻纤与尼龙界面相当于缺陷, 使MC 尼龙性能下降。      

磨碎玻璃纤维增强环氧树脂复合材料的制备及力学性能研究

用硅烷偶联剂对磨碎玻璃纤维表面进行改性,并制备玻璃纤维/环氧树脂复合材料,采用超声分散对复合材料分散处理,探讨不同磨碎玻璃纤维粉质量比对环氧树脂基复合材料压缩、拉伸性能的影响。研究表明,添加磨碎玻璃纤维后,环氧树脂的强度和硬度显著增强。当磨碎玻璃纤维掺量在15%~25%之间时,复合材料的综合力学性能最好,其压缩强度、压缩模量、拉伸强度最高达到67.1 MPa、1.68 GPa、57.6 MPa,与纯环氧树脂相比提高了24%、35%、34%;断裂伸长率随着掺量的增加逐渐降低,当含量达到30%时比纯环氧树脂的降低了48%,表明添加玻璃纤维粉后环氧树脂脆性增强。目数小粒径较大的玻璃纤维粉对环氧树脂力学性能增强效果更优,但影响程度不如含量对复合材料力学性能的影响大。     

低碳钢表面硅烷化处理对聚乙烯涂层结合强度的影响

利用硅烷偶联剂(KH-550,KH-560,KBM-7103)对低碳钢表面进行预处理,制备了聚乙烯(PE)涂层,通过对涂层的结合强度、抗热震性能等实验,研究了硅烷化处理对涂层性能的影响.结果表明:KH-560处理法能显著提高PE涂层的结合强度,比砂纸打磨、喷砂处理分别提高了40.3%,13.2%,而KH-550,KBM-7103不能显著提高PE涂层的结合强度;对于PE涂层的硅烷化处理,适宜的KH-560的浓度为5%(体积分数),水解时间为48h;"喷砂 KH-560"处理法抗热震实验后涂层的结合强度仅降低了10.9%,远低于其他处理方法热震后的下降幅度.     

提高白纸板折叠纸盒抗压强度的措施

探讨了国内外对于折叠纸盒抗压强度的研究进展,表明其影响因素有纸板的挺度、环压强度、厚度及纸盒的几何尺寸,并从提高白纸板挺度和环压强度、优化纸盒设计两方面提出了提高白纸板折叠纸盒抗压强度的措施.提高白纸板挺度和环压强度的措施有选择合适的浆料品种、打浆度、纸机,涂布、施胶和应用化学助剂等,优化纸盒设计包括优化纸盒结构和尺寸设计以及纸板纹向的正确使用.     

沥青基碳纤维及其混杂纤维增强尼龙1010复合材料结构与性能的研究

本工作研究了通用型沥青基碳纤维、玻璃纤维及它们的混杂纤维增强尼龙1010复合材料的结构与性能,并与相应的聚丙烯腈基碳纤维及其混杂纤维复合材料的性能作了系统的比较.实验结果表明,随短纤维含量的增加,复合材料的模量和强度线性增加,当纤维含量达到一定临界值时,其强度有所下降.聚丙烯腈基碳纤维增强尼龙1010复合材料比相应的沥青基碳纤维复合材料具有较好的力学性能,但后者通过与高强度玻璃纤维混杂增强,可提高其力学性能.本工作还研究了这些复合材料的断裂特征和它们的混杂效应.      

偶联剂对聚氯乙烯/粘土纳米复合材料结构与性能的影响

采用固相法、用自制的插层剂和偶联剂对粘土进行有机化插层改性制备出有机粘土;然后采用熔融插层法制备了聚氯乙烯(PVC)/有机粘土纳米复合材料。研究表明,偶联剂KH-560处理的有机粘土与PVC形成插层型纳米复合材料,偶联剂KH-550处理的有机粘土与PVC形成的则是剥离型纳米复合材料。PVC/有机粘土的拉伸强度和冲击强度都有显著提高;KH550处理的有机粘土对PVC的改性效果明显优于KH560处理的有机粘土的改性效果。     

The effect of alkaline and silane treatments on mechanical properties and breakage of sisal fibers and poly(lactic acid)/sisal fiber composites

The main goals of this work were to study the effect of different chemical treatments on sisal fiber bundles tensile properties as well as on tensile properties of composites based on poly(lactic acid) (PLA) matrix and sisal fibers. For this purpose, sisal fibers were treated with different chemical treatments. After treating sisal fibers the tensile strength values decreased respect to untreated fiber ones, especially when the combination of NaOH + silane treatment was used. Taking into account fiber tensile properties and fiber/PLA adhesion values, composites based on silane treated fibers would show the highest tensile strength value. However, composites based on alkali treated and NaOH + silane treated fibers showed the highest tensile strength values. Finally, experimental tensile strength values of composites were compared with those values obtained using micromechanical models.     

A study of the mechanical properties of short natural-fiber reinforced composites

The degree of fiber–matrix adhesion and its effect on the mechanical reinforcement of short henequen fibers and a polyethylene matrix was studied. The surface treatments were: an alkali treatment, a silane coupling agent and the pre-impregnation process of the HDPE/xylene solution. The presence of Si–O–cellulose and Si–O–Si bonds on the lignocellulosic surface confirmed that the silane coupling agent was efficiently held on the fibres surface through both condensation with cellulose hydroxyl groups and self-condensation between silanol groups.

The fiber–matrix interface shear strength (IFSS) was used as an indicator of the fiber–matrix adhesion improvement, and also to determine a suitable value of fiber length in order to process the composite with relative ease. It was noticed that the IFSS observed for the different fiber surface treatments increased and such interface strength almost doubled only by changing the mechanical interaction and the chemical interactions between fiber and matrix.

HDPE-henequen fiber composite materials were prepared with a 20% v/v fiber content and the tensile, flexural and shear properties were studied. The comparison of tensile properties of the composites showed that the silane treatment and the matrix-resin pre-impregnation process of the fiber produced a significant increase in tensile strength, while the tensile modulus remained relatively unaffected. The increase in tensile strength was only possible when the henequen fibers were treated first with an alkaline solution. It was also shown that the silane treatment produced a significant increase in flexural strength while the flexural modulus also remained relatively unaffected. The shear properties of the composites also increased significantly, but, only when the henequen fibers were treated with the silane coupling agent. Scanning electron microscopy (SEM) studies of the composites failure surfaces also indicated that there is an improved adhesion between fiber and matrix. Examination of the failure surfaces also indicated differences in the interfacial failure mode. With increasing fiber–matrix adhesion the failure mode changed from interfacial failure and considerable fiber pull-out from the matrix for the untreated fiber to matrix yielding and fiber and matrix tearing for the alkaline, matrix-resin pre-impregnation and silane treated fibers.     

Enhancement of the mechanical properties of polylactic acid/basalt fiber composites via in-situ assembling silica nanospheres on the interface

A valid strategy to tailor the properties of polylactic acid for more extensive applications was introducing filler.In this work,basalt fiber assembled with in-situ SiO2 nanoparticles on the surface was successfully prepared via hydrothermal method and it was further treated with coupling agent KH-550 to improve interfacial interaction between polylactic acid(PLA)and basalt fibers(BF).It was demonstrated that the introduction of BFS could increase the crystallization of PLA and resulted in forming trans-crystallization based on TG and DSC results.The tensile strength of PLA/BF composites raised from 39 MPa to 62.5 MPa with increasing the fiber loading from 1 wt％to 10 wt％.Furthermore,the interfacial interaction could be effectively improved by assembling SiO2(especially with 250 nm in diameter)on BF surface to build mechanical locking,which could keep the PLA matrix in place during the mechanical deformation with the tensile strength value raised from 62.5 MPa to 74.0 MPa.It is noticeable that the impact and flexural properties were effectively increased with the incorporation of in-situ SiO2 nanoparticles.The further KH-550 treatment made a positive impact as well.For instance,the impact strength and flexural strength of the sample with SiO2 and KH-550 modification were improved to 22.49 kJ/m2 and 146.83 MPa and it enhanced about 42.16％and 41.04％than those of neat PLA,respectively.Therefore,an efficient enhancement of mechanical performance was achieved and this concept of assembling in-situ SiO2 on silica-based fiber as a modifier was a novel and simple path to design the interfacial construction and properties of the polymer composites.