Effect of silane treatment on the Curaua fibre/polyester interface

ABSTRACT

Good adhesion at fibre/matrix interface of lignocellulosic fibres is crucial when substituting synthetic fibres in polymer composites. The great variability presented by those fibres requires diverse characterisation studies for better insights on fibre surface treatments and resin systems interactions. In this work, Curaua fibres were treated using silane coupling agents to improve their interfacial properties with polyester. The fibres were pre-treated using 4?wt% solution of NaOH and then treated with 5?wt% solution of (3-aminopropyl) trimethoxysilane (AMPTS) or triethoxymethylsilane (TEMS). Characterisation of the treated fibres was carried out using infrared spectroscopy, X-ray diffraction, thermogravimetric analysis and scanning electron microscopy. Fibre wettability and adhesion towards polyester was investigated using contact angle measurements and pull-out tests, respectively. The AMPTS treatment yielded a significant result of 20.2?MPa in interfacial shear strength (≈2.5 times that of the untreated fibre), attributed to the increase in availability of binding sites with polyester.     

Modification of polyamide fiber surfaces by micro-organisms

The properties of some polyamide fibers - polycaproamide (PCA), poly-p-amidobenzimidazole (PABI), poly-p-phenyleneterephthalamide (PPTA), poly-m-phenyleneisophthalamide (PPIA), and polyimide (PI) - treated by different micro-organisms that are abundant in nature (the bacteria Bacillus and Pseudomonas, and the fungi Aspergillus) were studied. The interfacial bond strength between these fibers (untreated and exposed to micro-organisms) and thermoplastic polymers such as polyethylene (PE), polycarbonate (PC), and polysulfone (PSF) was investigated by the single-filament composite and pull-out techniques. If the treatment time is not very long (1-3 weeks), the tensile strength of the fibers does not deteriorate. However, the topography of the surface undergoes considerable changes in some cases. The result of the treatment depends substantially on the chemical nature of the nutrient as well as on the micro-organism species. Two main avenues for fiber modification are possible: (1) decomposition of macromolecules in the surface layer, resulting in surface growth; and (2) adsorption of the metabolic products, which heal surface flaws and alter the chemical nature of the surface. The increase in the interfacial shear strength (IFSS) for the modified fiber-thermoplastic matrix systems was from 15% for the PCA/PE composite to 80% for the PABI/PSF and PABI/PC pairs. This increase was especially marked when a sublayer of a substance specially added to the nutrient, having better compatibility with the matrix, was formed by micro-organisms on the fiber surface.     

反渗透浓水对污水生化处理系统影响研究

采用反渗透排放的浓水作为冲厕生活用水,对冲厕后的浓水进行生化处理实验,实验结果表明:当反渗透排出的浓水电导率在1500微西以下时,对生化系统中的微生物没有影响,实验为化工生产污水零排放、循环经济提供了科学依据.     

氮气等离子体处理对芳纶与橡胶粘合性能的影响

研究氮气等离子体处理对芳纶帘线表面形态及其与橡胶粘合性能的影响。结果表明,氮气等离子体处理可在一定程度上提高芳纶帘线与橡胶的粘合性能;芳纶经氮气等离子体处理后再结合浸胶,粘合强度显著提高;高功率、长时间处理有利于芳纶帘线与橡胶粘合性能的提高,但会使芳纶帘线的强度下降。适宜处理条件为：功率100～125W,时间5～7min。     

焦化废水生化处理研究进展

焦化废水是一种典型的含难降解有机污染物的工业废水,除含酚类物质以外,还含有多种芳香烃和杂环类有机物,成分十分复杂,且该废水水量大,对环境污染严重。因此,焦化废水的处理研究一直是国内外环境工作者关注的焦点之一。概述了近年来焦化废水成分检测方法,系统介绍了焦化废水生化处理技术的最新研究进展,阐述了影响NH3-N、F^-、COD、有机污染物及色度去除的主要因素。     

农药含酚废水处理工艺与设备的改进研究

针对某工场农药含酚废水的生化—氧化—絮凝沉淀污水处理系统存在的工艺、设备问题,对原有污水处理系统中的调节池、厌氧池进水方式、曝气系统设备、污泥回流系统等进行了改造。运行结果表明,改造后,重新建立了厌氧系统与好氧系统污泥的培养与驯化体系,出水酚质量浓度0.5 mg/L,苯质量浓度2.72 mg/L,酚去除率达85%,pH 8～9,COD 53.2 mg/L,SS 27 mg/L,出水质量达到《污水综合排放标准》(GB 8978—1996)。     

Wetting kinetics and adhesion strength between polypropylene melt and glass fibre: influence of chemical reactivity and fibre roughness

A systematic experimental investigation with the purpose of quantifying the effect of the interactions between non-polar (unmodified) and polar (modified) polypropylene melts and treated fibre surfaces during wetting has been performed. The glass fibres were sized by aminosilane (γ-APS), γ-APS/polyurethane film former (γ-APS/PU) and γ-APS/polypropylene film former (γ-APS/ PP). Unsized fibres were used for comparison and were also coated with an azidosilane layer. Zeta potential and contact angle measurements were employed to investigate the surface properties of the treated glass fibres. The surface roughness was characterised using both atomic force microscopy and scanning electron microscopy. A method based on axisymmetric drop shape analysis was employed to determine the surface tension of the polymer melt. The wetting of the fibres by the polymer melt was investigated using the Wilhelmy balance technique. The wetting kinetics was different for different fibre surface treatments. The chemically reactive system based on azidosilane showed a better wetting than the other systems. The aminosilane/polypropylene film former (γ-APS/PP) treated fibre was also characterised by a fast wetting, most probably due to the physical similarity between the polymer and the fibre sizing and, thus, probable compatibility. In the receding case the differences between the reactive systems were smaller than they were for the advancing case. Higher adhesion tension calculated from the wetting measurements correlated well with higher adhesion strength determined from single fibre pull-out tests.     

浅析煤制甲醇废水的生化处理工艺

研究了物化+SBR工艺处理煤制甲醇生产废水的生化处理方法。该工艺技术成熟,物化处理单元可以保证SBR池安全、稳定地进水,生化处理单元可以保证出水水质。运行效果表明,对于煤制甲醇生产废水,采用物化+SBR工艺的方式具有良好的处理效果。     

超声波处理对芳纶帘线表面形态及与胶料粘合性能的影响

试验研究超声波处理对芳纶帘线表面形态及与NR/SBR胶料粘合性能的影响。结果表明 ,芳纶帘线的耐热温度可达 5 0 0℃ ;在蒸馏水中 ,超声波的空化作用可对芳纶帘线表面进行清洗和刻蚀 ,消除帘线表面的弱边界层 ;在碱性或酸性条件下 ,超声波作用可加快芳纶的水解 ,增加芳纶表面的活性基团 ,提高帘线与橡胶基质的静电吸附和化学键合作用 ,从而提高芳纶帘线与NR/SBR胶料的粘合性能 ;超声波处理芳纶时氢氧化钠溶液和硫酸最佳的质量分数均为 0 2 0 ,适宜处理时间分别为 10和 15min。     

含盐废水生化处理耐盐污泥驯化的研究

对两种活性污泥,即高盐环境的海边污泥和普通废水处理厂的污泥进行了耐盐污泥对比驯化研究.结果表明:经过一定时间的驯化.两种污泥都可以驯化成具有高降解性能的耐盐污泥,且都能有效地处理含盐废水.驯化后海边污泥在NaCl质量浓度为35 000 ms/L,COD_(Cr)容积负荷为1.8 kg/(m~3·d)时,出水COD_(Cr)去除率可达到97%以上;而普通污泥在NaCl质量浓度为15 000 mg/L,COD_(Cr)容积负荷为1.55 kg/(m~3·d)时,出水COD_(Cr)去除率可达到94%以上.同时对两种污泥在驯化过程中的驯化特点、生物学过程及系统的抗冲击性能进行了比较研究.与普通污泥相比,海边污泥具有驯化期短、耐冲击性能强等特点.     

Effects of plasma treatment on mechanical properties of rubber/cellulose fibre composites

Natural rubber materials reinforced with cellulose fibres have been studied with respect to crosslink density, tensile strength and stress relaxation. The fibres have been grafted with butadiene or divinylbenzene by plasma treatment. Chemiluminescence analysis was used to indicate the grafting on the surface of the cellulose fibres and also to estimate the effect of the plasma on the cellulose fibres. The results indicate the possibility of obtaining a surface layer on the fibres, which is a conceivable way of improving the mechanical properties of rubber composites.     

组合生化法处理难降解聚醚废水的工程实践

基于聚醚多元醇生产废水的水质特性和生化特性,通过处理试验,在工程中采用分类处理,预先膜分离回收废水中难降解的高分子聚醚多元醇,然后通过厌氧/好氧组合生物处理工艺处理.运行结果表明,废水排放指标达到GB 8978-1996一级标准与江苏省地方标准COD_(Cr)≤80 mg/L,效果良好.     

Mechanical properties of natural rubber/grafted cellulose fibre composites

Mechanical properties of natural rubber/allyl acrylate and allyl methacrylate grafted cellulose fibre composites are presented. Stress/strain measurements and dynamic mechanical measurements indicate that the adhesion between grafted fibres and matrix is better than that in samples containing untreated cellulose fibres. This makes it possible to vary the composite properties by varying the fibre type and/or fibre amount.     

印染废水处理技术的研究进展

印染废水组分复杂，常含有多种染料，色度深，毒性强，难降解，pH波动大，而且浓度高，废水量大，是难处理的工业废水之一。首先介绍了印染废水的组成及特征，然后将处理印染废水的方法分为物化处理法(吸附法、过滤法)、化学处理法(絮凝沉淀法、电解法、化学氧化法、光催化氧化法)和生化法加以介绍。并评述了各种处理方法的适用条件及处理效果，总结各种方法的优缺点。提出开发不同处理方法的有效组合和研究高效、经济、节能的印染废水处理反应器将是印染废水处理工艺研究发展方向。     

化工废水氮、磷生化处理技术研究进展

化工废水氮、磷污染控制对水体富营养化治理具有重要意义。总结了目前国内外比较成熟的氮、磷生化处理技术，并对各方法的优缺点及应用进行了分析。     

The three-fibre method for measuring glass fibre to resin bond strength

This paper presents a method developed to measure the bond strength of a fibre/resin bond. Equipment has been developed to enable the test to be carried out in a normal tensile testing machine, and the results to be followed by scanning electron microscopy. Bond strengths obtained by this method are in agreement with earlier results. There are, however, some problems related to the method, including reproductivity of the test, determination of the degree of polymerization of the resin and the use of very thin fibres. However, the method has been proved a very quick and relatively accurate indicator of the strengths of fibre/resin bonds.     

Characterization of adhesion performance of topcoats and adhesion promoters on TPO substrates

Adhesion of organic coatings to thermoplastic olefin (TPO) substrates in automotive applications has been an issue for makers of automotive parts since TPO was first used in exterior applications, primarily fascia. A widely used technique for assuring paint adhesion to TPO is the use of adhesion promoter primers based on chlorimated polypropylenes (CPO). Much research has been focused on understanding the forces involved at the interfaces of substrate, adhesion promoter, and topcoats resulting in the adhesion or the loss of adhesion in various environmental conditions. This study correlates the adhesion performance of CPO and nonchlorinated adhesion promoters (NCPO) as measured by peel strength with properties observed through microscopy techniques. Adhesion performance of CPOs, NCPOs, and blends are quantified through the use of 90° and 180° peel strength studies. Surface characteristics of adhesion promoters applied over a TPO substrate and cured at various temperatures are examined through the use of atomic force microscopy (AFM).     

采用生化微反应器对废水可生化性测定方法的初探

采用生化微反应器对废水可生化性的表征方法进行了初步的研究,提出了一种废水可生化性的检测方法,并将测定的指标定义为生化呼吸指数(Ks)。结果表明:在相同HRT的情况下,废水COD去除率的高低与废水的Ks呈对应关系;特殊菌种在很大程度上可以明显改变废水的Ks,同一种废水在不同的生化体系中也可以具有不同的Ks,随着生化体系中SS的增加,废水的Ks也逐渐上升。Ks比常用的B/C更能反映出实际生化体系中废水的可生化性,并将Ks=5.0作为评价废水可生化性的判定值,当Ks<5.0时,表明废水的可生化性较差;当Ks≥5.0时,表明这种废水的可生化性较好。     

氯离子选择电极在氯碱厂工业废水COD测定中的应用简

摘要：介绍了高含盐环氧丙烷废水采用传统好氧活性污泥＋接触氧化处理工艺中．不同含盐量运行条件下运行参数的变化以及各阶段生化处理效率的变化。