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。     

功率超声波在废橡胶再生中的应用

全世界每年要产生一千五百多万吨废旧橡胶,由于废橡胶具有三维稳定的化学结构,需要很长时间才能降解,堆放在大自然中,既污染环境,又浪费宝贵的资源,废橡胶的回收利用是解决这一问题的最好方法。再生橡胶的制造方法很多,近来出现的超声波脱硫法具有高效、环保、产品质量高等优点,被认为是最有希望的方法,已受到广泛关注。详细地介绍功率超声波在废橡胶脱硫中的应用、介绍近年来国际上的进展情况和一些典型的装置,具有一定意义。     

利用超临界乙醇脱硫再生废旧轮胎胎侧胶

以超临界乙醇为反应溶剂,对废旧轮胎的胎侧胶进行脱硫再生实验研究。考察反应温度、压力和时间对脱硫效果的影响,对脱硫后凝胶的物理性能和溶胶的化学结构进行表征分析,并讨论添加脱硫剂对脱硫胎侧胶的影响。研究发现,超临界乙醇中不同种类橡胶脱硫难易程度不同,脱硫后溶胶高分子平均相对分子质量高,主链结构完整,凝胶产物的玻璃化转变温度升高。分析表明,影响主链断裂的主要因素是反应温度,超临界乙醇脱硫过程中添加脱硫剂可以进一步促进交联键的断裂。     

超声波技术在空调除湿剂强化再生中的应用研究进展

对空调除湿剂(固体和液体)超声波再生技术机理及目前研究成果进行了总结,尤其是对固体除湿剂超声波强化再生效果、再生能耗及再生过程模型进行了论述,结果表明,超声波用于除湿剂强化再生能有效提高低品位能源在除湿空调系统中的利用效率,从而达到节能效果。同时根据实际应用情况分别给出了溶液和固体超声波再生装置的设计方案,并对该技术领域未来研究内容提出几点建议。     

吸附材料超声波再生的研究进展

超声波再生是处理吸附材料的有效途径之一。介绍了超声波再生技术的原理,分析了影响超声波再生吸附材料效率的主要因素。通过对超声波再生与传统的热再生的比较,探讨了超声波再生的优势与劣势,并对超生波再生技术的发展方向和趋势做了展望。     

空气涡轮制冷制取精细橡胶粉生产线

<正>目前回收废旧橡胶的方法大体上有两种,第一种是把废旧橡胶制成片壮的再生胶片的物理化学法;第二种是制成胶粉的机械方法。第一种再生胶的生产方法又可分为多种,工艺相差不大。其工艺流程为:废胶料→常温粗碎→常温细碎→净化筛分→脱硫→水洗→干燥→精炼→压片。该方法工艺陈旧,能耗大,污染严重。     

废旧锂离子电池中有价金属回收工艺的研究进展

锂离子电池广泛应用于移动电子设备、电动汽车和储能等领域,但由于生命周期有限和产品的更新换代,导致其报废数量与日俱增.对典型废旧锂离子电池的组分进行分析,并对有价金属回收的主要技术过程(包括预处理过程,钴的浸出过程,化学纯化过程和钴酸锂的修复再生过程等)进行了综合评述.在此基础上,提出了今后废旧锂离子电池资源化和无害化的发展建议.     

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。     

道路旧混凝土面层的再生利用探讨

将道路废旧混凝土拆除、生产成为再生集料,可以作为一种资源再次利用。本文介绍了道路废旧混凝土面层的拆除方法、旧混凝土再生集料的生产方法,对再生集料的物理、力学性质进行了系统的介绍。已有的试验和经验证明:道路旧水泥混凝土再生集料能够在道路的改建和新建中应用。     

Modified phosphate pigments as high performance reinforcing materials for rubber vulcanizates

This study is focusing on the synthesis of novel modified micronized phosphate pigments as reinforcing materials for the vulcanizates of styrene-butadiene rubber (SBR), natural rubber (NR) and their blends. The metal phenyl phosphate pigments were prepared via co-precipitation process from the reaction of equimolar ratios of the disodium phenyl phosphate solution and the water soluble salts of the investigated metals. The white prepared phosphate pigments were introduced in the rubber formulations to replace carbon black the highly common and commercial reinforcing material in rubber vulcanizates. The rheometric characteristics, physico-mechanical properties in addition to the accelerated aging properties of the rubber vulcanizates were investigated, discussed and interpreted in the light of previous studies. The results showed that, phenyl phosphate pigments exercised a great effect on the rheological characteristics (scorch time, cure time…etc.), and achieved high performance and pronounced mechanical properties. The stress and strain at yield and at rupture of the loaded rubber with modified phosphates are better than that loaded with carbon black and Hisil e.g. tensile strength data were (20.0–23.4), 18.01 MPa and 15.05 for rubber blend vulcanizates loaded with 30 phr of modified phosphate pigments, carbon black and Hisil, respectively.     

Effects of ground rubber having different curing systems on the crosslink structures and physical properties of NR vulcanizates

From extensive work on the properties of ground rubber (GR) filled compounds, it could be expected that cure behavior and physical properties of GR filled vulcanizates depend on the kind of rubber and curing agents used in rubber matrix and GR. The effects of conventional, semi-efficient and efficient curing systems of rubber matrix and GR on cure behavior and physical properties of GR filled vulcanizates are investigated. In addition, the variations of crosslink densities and structures of rubber matrix and GR are measured. The features studied strongly depended on the curing systems used in rubber matrix and GR.     

Scanning electron microscopy studies on flexing and tension fatigue failure of rubber

Vulcanizates of natural rubber and natural rubber/polybutadiene rubber blends have been tested for fatigue resistance separately under flexing and tension, and the fracture surfaces studied using a scanning electron microscope. The fatigue resistance ranking of the vulcanizates is almost the same from both types of tests. However, the mode of fracture depends on the type of test. In flexing failure, the dimple structure observed in unfilled natural rubber was absent in the blends. The presence of carbon black filler causes brittle fracture in both natural rubber and the blends. In tension fatigue, the fracture surface of the unfilled vulcanizates shows two zones, a rough zone and a tear zone. Brittleness observed in the black-filled natural rubber vulcanizate was less prominent in the blends.     

超声硫化的实验研究

成功地利用超声波对天然橡胶进行了硫化,所得试件展示了与传统硫化方法制得的试件相同的性能,但该工艺表现出许多传统硫化方法所不具备的优点。用滞后能量损失理论及声化学作用,解释了超声硫化的机理。得到了最佳硫化压力。     

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.     

The influence of hybrid phosphate–alumina pigments on properties of Ethylene-propylene-diene rubber composites

In this work Ethylene-propylene-diene (EPDM) rubber vulcanizates were pigmented with a new hybrid pigment containing nano-phosphate layer deposited on surface of micronized alumina. This new pigment contains both single and double-ion phosphates. Different rheological, chemical and physical properties of the nano-pigmented EPDM vulcanizates were studied and compared to the non-pigmented EPDM composites. These pigmented composite properties were studied in the presence and absence of maleic anhydride (MAH) which was employed as a compatibilizer. The bound rubber and cross-linking density were calculated. The results revealed that composites pigmented with 3Zn·1Ca phosphate/alumina/EPDM and 1Zn·3Ca phosphate/alumina/EPDM exhibited the best properties compared to other pigmented composites.     

新型含氨丙基聚硅氧烷基高温硫化硅橡胶的制备

以含氨丙基聚硅氧烷为基胶,含羧乙基聚硅氧烷为交联剂制备了新型高温硫化硅橡胶.通过实验我们确定了制备含氨丙基聚硅氧烷基硅橡胶的最佳条件,在此条件下制备的硅橡胶具有良好的机械性能.实验制备的硅橡胶的拉伸强度、撕裂强度、扯断伸长率和邵氏硬度分别为5.9MPa,26.6kN/m,260%和64ShA.     

天然橡胶与其环氧化物并用胶基复合材料的黏弹阻尼性能

为改善天然橡胶（NR）的阻尼性能,在密炼机中以质量比20：80混合不同环氧度环氧化天然橡胶（ENR）与天然橡胶制备ENR-NR并用橡胶基体,在橡胶基体的混炼与开炼过程加入其他填充组分（硫磺、促进剂2,2'-二硫代二苯并噻唑（DM）、促进剂N-环己基-2-苯并噻唑次磺酰胺（CZ）、ZnO、硬脂酸、炭黑）得到了宽温域阻尼ENR-NR基复合材料。采用橡胶加工分析仪和动态力学热分析仪,研究了ENR-NR混炼胶和硫化胶的动态力学和阻尼性能。结果表明：NR环氧化增强了分子链局部刚性,改善了胶体与填料的黏结性,但ENR吸附较多炭黑后不易均匀分散于连续相NR中。因此,ENR-NR并用混炼胶的黏度和储能模量随ENR环氧度增大而增加;在NR中加入ENR可改善硫化胶的弹性和阻尼性能。ENR-NR并用胶的有效阻尼温度范围拓宽到较高温度,环氧度为25的ENR与NR并用后,有效阻尼温度范围为-57~1℃,明显宽于NR的-57~-20℃,但高环氧度并用胶则出现阻尼失效区。加入少量ENR对NR的硬度、模量和断裂伸长率影响不大。     

Effect of different curing systems on the mechanical and physico-chemical properties of acrylonitrile butadiene rubber vulcanizates

In the present study, the effect of different curing systems including sulfur, dicumyl peroxide, dicumyl peroxide/coagent and radiation/coagent on the mechanical and physico-chemical properties of acrylonitrile butadiene rubber (NBR) was studied. In order to correlate, the effect of curing systems on rubber, the comparison was carried out at comparable value of volume fraction of rubber in swollen gel (V_r) for NBR vulcanizates. Mechanical properties like tensile strength, elongation at break, modulus, Young’s modulus, tearing strength and abrasion loss of vulcanizates have been followed up for comparison. In addition, physico-chemical properties like swelling ratio, soluble fraction, and cross-link density were investigated. On the other hand, the effects of fuel, thermogravimetric analysis, and thermal ageing have been studied.