超声波场致作用在聚合物加工中的最新进展

概述了超声波场致作用在聚合物成型、改性以及橡胶脱硫中的研究进展,介绍了超声波场致作用在降低聚合物粘度、提高挤出产量、改善聚合物的力学性能和外观质量及实现废旧橡胶的脱硫、再生循环利用方面的应用现状。还介绍了超声波场致作用在超声混炼改性方面的研究进展。     

废橡胶超声波再生的研究

废旧橡胶的再生,是关系到环保和资源综合利用的重要课题,超声波再生法,被认为是最具发展前途的再生方法之一,本文对废旧轮胎胶粉的超声波脱硫过程进行了实验研究。结果表明,超声波能有效地对硫化胶进行脱硫再生,超声波的振幅和作用间隙对脱硫过程起关键作用。     

基于不同温度作用下橡胶再生方法与原理研究进展

高效、绿色环保的废橡胶再生技术是世界橡胶工业可持续发展的难点。温度对橡胶再生有重要影响,文中根据橡胶交联键断裂对温度的敏感程度,从高温(200℃)、中温(150～200℃)、中低温(100～150℃)及低温(100℃)4个温度区间,分析了不同温度下废橡胶的脱硫再生方法及机理,系统性阐述了不同再生工艺的发展瓶颈及应用前景,以期为橡胶再生行业技术发展提供借鉴。最后展望了废旧橡胶回收再利用产业的发展方向。     

废橡胶脱硫再生技术及新型再生剂研究进展

废橡胶再生技术是世界橡胶工业一直以来的研究重点和难点,有效再生废橡胶是节约资源、保护环境的必然要求。本文综述了典型的废橡胶物理、化学再生技术及原理,系统阐述并评价了双螺杆挤出机再生法、利用超临界CO2再生法、微生物再生法、力化学再生法等几种新型并具有较好应用前景的再生方法,并对废橡胶化学再生剂的最新研究进展进行了概述。废橡胶再生技术的核心是在获得较高线性化的同时,最大程度的保护橡胶主链。同时,发展一种高效、节能、环保的再生技术将是今后努力的方向。     

我国废橡胶资源的利用现状和发展趋势

随着经济的不断发展,我国各行业的发展都呈现出一片欣欣向荣的势头。但是与此同时,许多工业企业进行生产后的废弃物也逐渐增多起来,就比如说我国的橡胶产业,其在生产之后首先会产生很多余料或是废料,而且在产品投入使用后,随着时间的推移,产品会慢慢失效,然而橡胶资源却还存在,若不对废橡胶资源进行再利用,那么将会产生很大的浪费。文章从我国废橡胶资源的利用现状出发,展望了我国废橡胶资源利用的发展趋势,同时介绍了废橡胶资源当中最大的成分胶粉的利用,给我国废橡胶资源的利用提供了一条道路。     

澳大利亚研发废塑料废橡胶炼钢新技术

澳大利亚新南威尔士大学教授维娜.萨哈吉瓦拉研发出一种将废橡胶、废塑料用于钢铁生产的新方法—聚合物注入工艺。不仅可以大大减少废橡胶、废塑料造成的环境污染,还可以有效降低钢铁生产成本。废橡胶和废塑料中含有很多碳,将废弃橡胶和塑料作为碳元素的替代品投入电弧炼钢炉中,原来被"锁"在废弃塑胶中的     

橡胶沥青半柔性路面施工技术研究

作为一种新型筑路材料,废橡胶粉在工业化生产的推动下得到深入发展。在路面结构施工中,掺加适量橡胶材料,可改善沥青混凝土性能。该文将橡胶沥青应用于半柔性路面,在充分了解半柔性路面结构及特点的基础上,依托具体工程,对其配合比、施工工艺进行了探讨,经施工表明,橡胶沥青半柔性路面具有良好的应用前景。     

废旧橡胶脱硫再生及其在塑料中的应用研究进展

随着工业的迅猛发展,生胶资源日益趋紧,废旧橡胶正逐渐成为严重的"黑色污染"。对国内外有关废旧橡胶的脱硫再生方法以及脱硫橡胶在塑料中的应用研究进行了综述,分析了目前存在的问题,并对其前景进行了展望。     

橡胶改性沥青及老化特征微观尺度分析

为了在微观尺度下分析橡胶改性沥青及老化特征,制备了普通橡胶沥青和脱硫橡胶沥青,首先分析了两种橡胶改性沥青制作前后橡胶颗粒的变化特征,然后通过凝胶渗透色谱实验建立了两种橡胶改性沥青的分子量分布与宏观路用性能的对应关系,最后综合宏观技术指标与红外光谱半定量分析研究了两种橡胶改性沥青的老化特征。结果表明,经过高速剪切工艺大粒径的脱硫橡胶粒在沥青里大多分散成无明显颗粒的细小物质,而普通橡胶粉剪切后基本保持其原有颗粒核心;普通橡胶沥青具有最高的大分子LMS的比例,这与其最优异的高温稳定性与低温抗裂性相对应;普通橡胶沥青的TFOT短期老化中存在着强烈的胶粉持续溶胀作用,但在PAV长期老化中主要发生氧化老化作用,而脱硫橡胶沥青的TFOT短期老化和PAV长期老化均以沥青的氧化老化为主;普通橡胶沥青比脱硫橡胶沥青更加耐受TFOT短期老化。     

超高压水射流破碎轮胎橡胶的脱硫机理

利用超高压水射流装置将废旧子午线轮胎胎面胶破碎为橡胶粉末并进行橡胶回收,运用低场核磁共振、红外光谱、扫描电镜、粒度分析等手段对橡胶粉末的物理和化学结构进行表征。结果表明,橡胶材料在破碎过程中发生了常温脱硫反应,脱硫效果随着水射流压力的提高呈先升高后降低的趋势,并在200 MPa压力处达到最佳,材料内部交联信号强度下降到54.85%。根据红外光谱推测了可能发生的化学反应,研究了引发脱硫反应的力学因素,认为水射流引起的剪切应力场作用是脱硫反应发生的主要原因。     

废旧橡胶热-机械剪切脱硫过程及机理

利用元素分析仪、红外光谱仪研究了废旧橡胶热-机械剪切脱硫过程及其机理。在未加任何脱硫剂的情况下,利用双螺杆挤出机提供的热能和强剪切作用对硫化橡胶进行了脱硫回收,研究发现,硫化橡胶的交联密度下降到71%,恢复了再加工性能,并且微观结构也发生了显著的变化。提出了交联硫键断裂后以活性硫侧挂基形式存在的理论,解释了再生胶脱硫后不需外加硫磺仍可以硫化的现象。溶胶的红外光谱给这一理论提供了有力的证明。根据脱硫反应前后官能团的变化推测出脱硫反应可能的机理。     

废旧轮胎橡胶的常温应力诱导固相力化学脱硫化研究

利用固相力化学反应器实现对废旧轮胎橡胶的常温力化学脱硫化。实验结果,表明胶粉的交联密度和凝胶含量随碾磨次数增加显著降低,通过碾磨,再硫化橡胶的力学性能得到显著提高。碾磨40次后,拉伸强度由碾磨前2.3 M Pa提高到10.9 M Pa;断裂伸长率由碾磨前的69.6%提高到290.0%。再硫化胶的断面形貌分析表明,用脱硫胶制得的胶片具有良好的界面结合。     

Blends of ultrasonically devulcanized tire-curing bladder and butyl rubber

The devulcanization of the butyl rubber based tire-curing bladder was carried out with a grooved barrel ultrasonic extruder. The devulcanized rubber was blended at different ratios with the carbon black filled virgin butyl rubber and cured. The rheological and mechanical properties, as well as gel fraction and crosslink density of the revulcanized rubber and vulcanizates of blends have been measured. The blend of ground tire-curing bladder and carbon black filled butyl rubber has also been prepared for comparison purpose. Compared to the blend containing the ground rubber, compounding of the blends containing the devulcanized bladder were easier and their vulcanizates had smoother surface. In addition, the vulcanizates containing devulcanized tire-curing bladder and virgin rubber showed substantially improved mechanical properties than the vulcanizate of the devulcanized rubber alone.     

Ultrasound devulcanization: comparison of synthetic isoprene and natural rubbers

Sulfur-cured vulcanizates of unfilled synthetic isoprene rubber (IR) were prepared and successfully devulcanized in a continuous co-axial ultrasonic reactor. Die pressure characteristics and ultrasonic power consumptions were measured. Network structures of the virgin vulcanizates, devulcanizates and revulcanizates were characterized by gel fraction and crosslink density according to the classic swelling method. The molecular characteristics of the sol generated by ultrasound treatment were determined by GPC. Kinetics of revulcanization, rheological properties of the devulcanizates and mechanical properties of the revulcanizates were compared with those of virgin uncured IR and their vulcanizates. In addition, a comparison of the cure behavior, devulcanization characteristics, network structures and the mechanical properties was made between IR and the natural rubber (NR) reported earlier. Simulations on the correlation of the normalized gel fraction and the normalized crosslink density show that these two rubbers have almost equivalent probability of main chain scission and crosslink rupture ratio, which is probably determined by the main chain structure of both rubbers consisting of cis-1,4-isoprene.     

轮胎胶高剪切应力诱导脱硫反应的影响因素

采用在轮胎胶粉与三元乙丙橡胶(EPDM)混合物的熔融挤出过程中提高双螺杆挤出机螺杆转速的高剪切应力诱导方法,研究了轮胎胶粉品种和烷基酚多硫化物促进剂对轮胎胶脱硫共混物的凝胶含量、溶胶分子链结构及脱硫共混物共混丁苯橡胶再硫化材料力学性能的影响。试验结果表明,胶粉品种对所得脱硫共混物溶胶中的双键含量及再硫化材料的拉伸强度具有重要影响;烷基酚多硫化物促进剂420和450具有明显促进脱硫反应和抑制交联副反应的作用,有效减小再硫化材料凝胶粒子尺寸,聚合型促进剂450兼具有抗氧化降解和抑制加成副反应的功能。     

Fresh properties of self-compacting rubberized concrete incorporated with fly ash

Solid waste management is one of the major environmental concerns in all over the world. High amounts of waste tires are generated each year and utilization of this waste is a big problem from the aspects of disposal, environmental pollution, and health hazards. In the production of self-compacting concrete, the incorporation of waste tires as partial replacement of aggregates is very limited. However, the use of waste tires might join the characteristics of self-compacting concrete (high flowability, high mechanical strength, low porosity, etc.) with the tough behavior of the rubber phase, thus leading to be a building material with more versatile performances. Thus, in this study, the usability of untreated crumb rubber as a partial substitute of fine aggregates with and without fly ash in the application of self-compacting concretes was investigated experimentally. For this purpose, a water–cementitious material ratio (0.35), four designated crumb rubber contents (0, 5, 15, and 25% by fine aggregate volume), and four fly ash content (0, 20, 40, and 60%) were considered as experimental parameters. Test results indicated that use of crumb rubber (CR) without fly ash (FA) aggravated the fresh properties of self-compacting rubberized concretes (SCRC) (slump flow diameter, T₅₀ slump flow time, V-funnel flow time, L-box height ratio, initial and final setting times, and viscosity). However, the use of CR with FA amended the fresh properties of SCRC.     

基于LFM的橡胶脱粘超声检测方法研究

针对SYS510e型空气弹簧底板的金属橡胶粘接结构橡胶脱粘缺陷超声检测难以辨识问题,提出采用改进的线性调频脉冲代替传统窄脉冲作为超声波激励信号,增大超声检测的信号能量和频谱宽度。在宽频带超声检测的基础上,采用小波包-奇异值分解方法解析超声回波在不同粘接状态、不同频率范围的时频能量分布,提取更稳定、一致性更好的橡胶脱粘辨识特征值。根据特征训练BP神经网络对空气弹簧的橡胶脱粘缺陷进行超声C扫描检测。结果显示,基于改进的线性调频脉冲激励的超声检测方法能够准确有效地辨识橡胶脱粘缺陷的位置和轮廓,满足对SYS510e型空气弹簧的超声脱粘检测需求。