一种环保可降解水泥编织袋

本文介绍了一种环保可降解水泥编织袋,包括袋体,袋体的表面固定设有第一PLA生物降解编织布,第一PLA生物降解编织布的内壁通过粘片与第二PLA生物降解编织布的外壁粘接,第二PLA生物降解编织布的内壁通过PLA纤维片与第一PLA生物降解膜的外壁固定连接,袋体的顶端固定设有第一加强布,本技术的有益效果是:本技术一种环保可降解水泥编织袋,通过粘片将第一PLA生物降解编织布与第二PLA生物降解编织布连接,并且在第二PLA生物降解编织布的内壁设置PLA纤维片,提高了袋体的强度和韧性,袋体不易破损,通过设置第一加强布和第二加强布,提高了袋体两端的抗撕裂能力。     

全降解PLA/PBAT/ESO保鲜膜在草莓保鲜中的应用研究

目的 采用全生物降解材料PLA/PBAT/ESO复合膜替代PE保鲜膜，并应用于水果保鲜包装。方法 测定市购PE膜和实验室自制PLA/PBAT/ESO保鲜膜的透湿性、透气性及力学性能，并以新鲜草莓为保鲜对象，以无包装防护为空白对照，研究PE保鲜膜、全降解PLA/PBAT/ESO保鲜膜在贮藏温度4 ℃下对草莓果实的保鲜效果。结果 相较于PE保鲜膜，全降解PLA/PBAT/ESO保鲜膜的效果更佳，其透湿透气性和力学性能更优，能够有效抑制果实在贮藏过程中可溶性固形物含量、硬度、可滴定酸含量、维生素C含量的下降，保持草莓的口感、风味和营养成分。结论 由于全降解PLA/PBAT/ESO保鲜膜的透气性和透湿性高于PE保鲜膜，减少了结露现象，减缓了微生物的滋长，能够有效地延缓草莓这类湿敏性水果产品的腐败变质进程，维持果实的贮藏品质。     

生物可降解脂肪族聚酯在陕西土壤中的降解行为

以西安当地土壤及西安某污水处理厂的活性污泥为降解介质,对生物可降解聚酯聚乳酸(PLA)、聚丁二酸丁二醇酯(PBS)和聚己内酯(PCL)的降解性能进行了研究,并对它们的降解机理进行了初步探讨。根据偏光显微镜和扫描电镜的观察表明,降解后的聚酯膜表面均有明显被侵蚀的痕迹;在陕西当地土壤中,PCL的降解速度最快,PLA次之,PBS最慢。红外光谱表征了这三种聚合物降解前后的化学结构。     

生物降解塑料在国内外的研究进展及发展趋势

近年来,世界各国均加大力度禁止和限制不易回收、易污染的一次性塑料产品。生物降解塑料成为替代一次性塑料产品的最佳选择。生物降解塑料分为生物基和石化基两大类。前者按制作方法细分为完全生物降解塑料（全淀粉生物降解塑料、微生物发酵和化学合成共同参与获得的生物降解塑料、微生物合成型生物降解塑料、共混型生物降解塑料）和不完全生物降解塑料。后者是以煤或石油等化石能源为原料,用化学合成法由单体聚合而成,代表性品种有聚丁二酸丁二酯（PBS） 、聚己二酸对苯二甲酸丁二酯（PBAT）、聚碳酸亚丙酯（PPC）等,该类塑料均基于脂肪族聚酯,分子链上的酯基结构决定了它们易被微生物或酶降解。从上述各类生物降解塑料的加工制作方法、性能特点、应用场合以及全球、国内外产能状况展开论述。未来,我国应重点发展淀粉基、PLA、 PBAT等三大生物降解塑料,应重视对高分子设计法的研究。     

PBS/PHB聚酯材料的生物降解性

将不同比例的聚丁二酸丁二醇酯/聚羟基丁酸酯(PBS/PHB)共混物分别放入陕西当地的土壤培养液和熟化过的堆肥培养液中进行微生物兹化反应,以研究它们的降解性,并通过Tg、X射线衍射(WAXD)、扫描电镜(SEM)对共混物的热稳定性、结晶度、表面形态进行了研究。结果表明,共混物在堆肥培养液中降解60d后的质量损失率达到62%,比纯PBS快,且随着PHB含量的增加,降解速度随之加快;共混物在土壤培养液中的降解趋势相同;对降解前后膜的表面形态观察发现,在土壤培养液中膜降解后有较明显的微生物侵蚀痕迹,在堆肥培养液中则出现了较大的孔洞。     

生物表面活性剂对堆肥中含烃有机质降解过程的影响

进行了将生物表面活性剂引入堆肥过程的实验研究。采用好氧堆肥法,模拟堆肥中石油烃污染,加入不同的生物表面活性剂发酵液对堆肥过程中的石油烃进行降解,将实验组与空白样进行对照,结果发现,生物表面活性剂的加入不仅可改善堆肥环境,提高堆肥效率,还对堆肥过程中石油烃的降解有促进作用。实验证明,鼠李糖脂发酵液的效果比莎梵婷发酵液的效果好。     

光氧化TiO_2/PEO/LDPE复合薄膜的生物降解性能

以聚氧乙烯(PEO)为亲水改性剂、纳米TiO_2颗粒作为光催化助氧剂,与低密度聚乙烯(LDPE)树脂复合制备了光氧化-生物降解TiO_2/PEO/LDPE纳米复合薄膜。通过密封堆肥和土壤微生物的降解实验,研究了该复合薄膜在空气中紫外光氧化降解后的生物降解性能。结果表明,TiO_2/PEO/LDPE复合薄膜在UVA340的紫外光照射600h后,发生了明显的降解,羰基指数增大,产生了大量羰基类的化合物,结构发生明显的破坏;光氧化后的薄膜碎片经过180d的堆肥或254d的土壤微生物降解后,其矿化率达到15.26%,薄膜表面长满了孢子及大量的菌丝,能够为微生物的生长提供所需的碳源。PEO的加入能提高纳米TiO_2在LDPE基体中的亲水性,从而提高其光催化氧化活性,使得LDPE薄膜的光氧化降解程度明显增大,有利于其后续的生物降解。     

生物降解塑料聚乳酸及其工业应用

在全球变暖、石油紧缺、原油供应不稳定及其价格剧烈变动的大形势下,生物降解塑料受到了更多的关注。其中,聚乳酸（PLA）材料是第一个形成商业化规模的生物降解塑料产业,它是由淀粉糖发酵生成,不需以石油为原料,在堆肥条件下可以完全生物降解,被认为是最具竞争力的可再生生物基塑料。许多其他类似的生物基或者生物降解塑料诸如Ecoflex、PHBV、PBS（聚丁二醇丁二酸酯）等,他们的价格几乎都是聚乳酸价格的2-3倍。     

聚己二酸对苯二甲酸丁二酯(PBAT)共混改性聚乳酸(PLA)高性能全生物降解复合材料研究进展

聚乳酸(PLA)作为一种可降解、可再生的聚合物,其优异的生物相容性和高强度、高模量的力学性能引起了许多学者的关注。聚乳酸基生物复合材料自进入人们的视野以来,由于其固有的延展性差、冲击强度低,加工过程结晶速率慢,结晶度小等缺陷,严重阻碍了其发展。关于PLA的改性研究在近十年里从未间断过,主要集中在增塑改性、增强改性、增韧改性。增塑改性是指向PLA中加入乳酸低聚物、柠檬酸酯、聚乙二醇等小分子化合物,减少PLA分子链间的相互作用,改善PLA的塑性,断裂伸长率大幅度提高,但增塑剂易渗出、迁移是如今面临的一大难题;增强改性是指向PLA加入无机填料或纳米粒子(二氧化硅(SiO2)、二氧化钛(TiO_2)、碳酸钙(CaCO_3)、滑石粉(Talc)、蒙脱土(MMT)等)引发异相成核,改善PLA的结晶性能,但无法从根本上解决材料韧性差的缺陷;增韧改性是指加入橡胶粒子或热塑性弹性体(天然橡胶(NR)、热塑性聚氨酯(TPU)、聚碳酸酯(PC)等),虽然在一定程度上改善了PLA的韧性,但PLA的生物降解性无法保证;随着一些可降解聚酯(聚己内酯(PCL)、聚丁二酸丁二醇酯(PBS)、聚己二酸对苯二甲酸丁二酯(PBAT)等)的产生,在不改变降解性能下,对PLA进行有效的增韧改性,是聚乳酸改性研究的主要方向和研究热点。PBAT作为一种可降解聚酯聚合物,链段兼具长链脂肪烃的柔性和芳环的刚性,赋予了其优异的柔韧性,与其他聚酯材料相比,这一优势是作为增韧改性PLA的最佳选择。在早期PLA/PBAT的研究过程中就发现,由于分子链段上结构的巨大差异,PBAT与PLA的相容性差导致共混物力学性能不佳。近十年里,研究者在聚合物共混改性的基础上,选择合适的第三组分对PLA/PBAT共混体系进行改性,并取得了丰硕的成果。目前,PLA/PBAT共混体系的增韧后冲击强度由纯PLA的2.3 kJ/m2提高至61.9 kJ/m2。本文归纳了PBAT增韧改性PLA共混体系复合材料的研究进展,分别对物理共混(无机填料或纳米粒子和物理相容剂)、反应性共混增容剂改性PLA/PBAT体系进行了介绍,分析了PLA/PBAT共混改性体系面临的问题并展望其前景,以期为制备高性能全生物降解PLA/PBAT复合材料提供参考。     

竹纤维/聚乳酸可生物降解复合材料自然降解性能

通过注射成型工艺制备竹纤维/聚乳酸（BF/PLA）可生物降解复合材料。利用X射线衍射（XRD）、凝胶渗透色谱（GPC）、三维视频显微镜及扫描电镜（SEM）等分析手段研究了BF/PLA复合材料自然降解性能。研究结果表明：BF/PLA复合材料自然降解过程中BF首先降解,PLA逐步分层缓慢降解,复合材料质量逐渐减少;PLA分子链上酯基与水反应,分子链不断断裂,结晶度减小,平均分子量降低,分子量分布变窄;复合材料颜色变深,表面变得粗糙不平,部分裸露的BF清晰可见,其拉伸强度和冲击强度逐渐下降。12个月后,BF/PLA复合材料质量损失率达到8.87%,PLA重均分子量降低了25.9%,复合材料的冲击强度和拉伸强度分别降低了44.0%和43.8%。BF/PLA可生物降解复合材料在土壤中的自然降解效率较低。     

LDPE/有机金属降解剂/配合剂体系降解性的研究

以低密度聚乙烯（LDPE）／铁（或锡）的有机合物／含氮有机物为降解体系,制成薄膜样品,于模拟堆肥环境中降解,跟踪取样,测定其粘均分子量及氢过氧化物浓度([POOH])变化,另外,进行了傅立叶变换红外（FT－IR）和差示扫描量热分析（DSC）测试,结果表明,所选用的某些体系能够在堆肥条件下高效降解,薄膜样品在降解60d后分子量大幅度降低,羟基含量,结晶度呈现明显的增高趋势,降解程度受降解剂种类,配合剂种类及含量,降解环境等诸多因素影响,所测[POOH]变化趋势与分子量变化存在着关联性,这为降解机理的进一步讨论打下了基础。     

Effect of electron beam treatments on degradation kinetics of polylactic acid (PLA) plastic waste under backyard composting conditions

The effects of electron beam irradiation on backyard composting behaviour of polylactic acid (PLA) polymer were evaluated. Samples (10 mm² × 0.75 mm) from thermoformed PLA drinking cups were exposed to 10 MeV electron beam irradiation at doses of 0, 72, 144 and 216 kGy. Irradiated PLA samples were placed in heat‐sealed, plastic screen and added to organic feedstock in a rotating composter within a computer‐controlled environmental chamber for 10 weeks at 35°C. Changes in weight, structural integrity and molecular weight were assessed over time. Results show that irradiation enhanced PLA breakdown. PLA weight decreased by increasing amounts as irradiation dose increased. Sample brittleness increased with irradiation dose and composting time. Finally, PLA molecular weight decreased as irradiation dose and compost time increased. Molecular weight D values for irradiated PLA were found to be about 430 kGy. After 1 week in a typical backyard composter, molecular weight D values increased to about 560 kGy and then fell to about 380 kGy after 2 weeks of composting. Samples irradiated at 216 kGy showed a reduction in weight of 9.4% after 10 weeks of composting, and a reduction of weight‐average molecular weight of 93.7% after 6 weeks. Copyright © 2008 John Wiley & Sons, Ltd.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.