Surface modification of MWNTs with BA‐MMA‐GMA terpolymer by single‐step grafting technique

In this article, a facile strategy was developed to prepare BA‐MMA‐GMA/MWNTs (multiwalled carbon nanotubes) hybrid nanoparticles as nanofillers in rubber by single‐step grafting technique. First, a new macromolecular surface modifier butyl acrylate (BA)‐α‐methyl methacrylate(MMA)‐glycidyl methacrylate (GMA) terpolymer was synthesized via radical copolymerization. Afterward, this terpolymer modifier was covalently grafted onto the surface of crude MWNTs by single‐step grafting technique. The structure, surface properties, and thermal stability of modified MWNTs were systematically investigated by FTIR, TGA, and TEM. FTIR results showed that BA‐MMA‐GMA terpolymer was successfully grafted onto the surface of MWNTs. TGA indicated that the optimum mass fraction of macromolecular modifier coated on the surface of MWNTs was 9 wt %. TEM images revealed that an organic coating layer was formed and the modified MWNTs showed good dispersibility in acetone. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

The innovative use of low heat input in welding: experiences on ‘cladding’ and brazing using the CMT processPaper presented at the 4th National Welding Day,Workshop: “Brazing”, Genoa, 25–26 October 2007.

As is well known in the field of welding technology, the heat input in a joining process is a defining factor of the results that can be obtained in numerous aspects directly affecting metallurgical phenomena, technological properties and the integrity of the welded joint, as well as deformations and residual stresses. Furthermore, a different heat input can be decisive on process productivity and economy.

This article concerns tests conducted in the IIS Special Welding Process laboratory with the collaboration of Arroweld Italia pertaining to two technological subjects of considerable interest, such as ‘cladding’ with high corrosion resistance alloys and thin layer brazing, both using continuous wire welding methods with gas shielding, in an entirely particular version known as ‘Cold Metal Transfer – CMT^®’.

In the case of ‘cladding’, the most critical aspects of anticorrosion overlay, such as penetration into the substrate and level of dilution, which frequently compromise the intrinsic corrosion resistance of the coating, are investigated.

On the other hand, with regard to brazing, the degree of deformability of brazed structures is investigated, as well as the impact of the process on the mechanical properties of the base material and any influence, or otherwise, of the presence of galvanizing layers on brazed joint quality (bonding, spraying, etc.).     

Optimization of Ti6Al4V titanium alloy laser–arc hybrid weld parameters

This article reports the results of a study aimed at using statistical methods to optimize the parameters for laser–arc hybrid butt welding of Ti6Al4V titanium alloy sheets with a thickness of 3.0 mm. The study has examined the effects of the hybrid welding process parameters, such as laser beam power, arc pulse frequency, arc length, arc current, wire speed, laser and arc relative positions, and weld speed. Microstructure has been studied using light microscopy and morphological analysis of weld bead cross sections. This article reports the results of energy and morphological tests.     

The development of conventional welding processes in naval construction

In recent years, analysis of the development of joining processes has resulted in the identification of two trends: the refinement and specialization of traditional processes on the one hand, and the development of novel technologies on the other hand. This dual line of trends has sometimes led to points of contact, with the development of the so-called hybrid technologies, involving the use of joining processes based on different physical principles for the creation of a single joint. The scope of this article is to provide a framework view of the state of development of conventional joining technologies with regard to shipbuilding applications.     

Modification In Situ of EPDM Filled with Carbon Black by Glycidyl Methacrylate

A method of chemical modification in situ of ethylene-propylene-diene rubber (EPDM) filled with carbon black was studied. A bifunctional monomer, glycidyl methacrylate (GMA), was used as the modifier to improve the dispersibility of carbon black in the rubber and to enhance the mechanical properties of EPDM vulcanizates. The effects of GMA on the structure and properties of EPDM vulcanizates such as determination of cross-linking density and vulcanizing properties as well as mechanical properties were investigated by FT-IR, SEM, and DMTA. The results showed the addition of GMA into carbon black filled EPDM compounds could remarkably improve the mechanical properties of the vulcanizates. The optimum content of GMA was about 5.0 phr when the content of carbon black was 50 phr. The reason for improvement of the mechanical properties might be attributed to the chemical combinations between rubber macromolecular chains and carbon black surfaces by GMA. The action of GMA was similar to a cocuring agent and a coupling agent.     

Preparation and Characterization of Some Terpolymer Latices and their Application as Finishing Agents for Cotton Fabric

Abstract:

This work describes the synthesis, characterization, and evaluation of terpolymer latex prepared from glycidyl methacrylate (GMA), butyl acrylate (BuA), and Styrene (St). Five terpolymer latex samples were prepared by varying the composition ratio of BuA or St from 10% to 70% and keeping the GMA at a constant composition ratio of 20%. The other three terpolymer latex samples were also prepared by varying the composition ratio of GMA from 10% to 30% and equal composition ratios of both BuA and St. Fourier transform Infrared (FTIR) spectroscopy was used to assure the occurrence of the polymerization reaction. The morphological and rheological properties of some prepared terpolymer latices were determined. It was found that the average particle diameter, ¯D_v, of the prepared latices generally increased with an increase in the acrylic content. The rheological measurements revealed that the terpolymer latices were characterized by pseudoplastic rheological behavior. Some of the latices were used in treating cotton fabrics and the data show an increment in the air permeability resistance as well as in abrasion resistance.     

汽车工业滤纸浸渍乳液的合成

介绍了一种制备汽车工业滤纸浸渍乳液的方法。采用单体预乳化、半连续滴加工艺,阴非离子乳化剂混合使用,以丙烯酸丁酯、苯乙烯为软硬单体,以有机硅氧烷A-1706、甲基丙烯酸缩水甘油酯、N-羟甲基丙烯酰胺进行交联改性,制得固含量为50%、Tg值为30℃的乳液。结果表明：当软硬单体配比为32∶68,有机硅氧烷用量为单体总量的0.8%,N-羟甲基丙烯酰胺用量为3.5%,甲基丙烯酸缩水甘油酯用量为1.0%,能够显著提高乳液综合性能;润湿剂用量为乳液总量的2.0%时,乳液润湿效果好,涂布速度快,提高了生产效率。     

高聚物增强木质基复合材料的结构与性能

为探索性能优异的高聚物增强木质基复合材料的制备方法, 以大青杨木材为研究对象, 选用双功能性单体甲基丙烯酸缩水甘油酯(GMA)和丙烯酸类单体甲基丙烯酸甲酯(MMA), 通过加热引发聚合的方式制得P(GMAcoMMA)/木材复合材料。利用SEM、 FTIR和XRD表征其结构, 并测试其相关性能。结果表明: GMA的加入, 使高聚物与木材细胞壁紧密接触, 界面相互作用力增强; GMA一端的环氧基团, 与木材细胞壁上的羟基充分发生了化学反应, 其双键与MMA单体发生自由基共聚合反应, 从而使P(GMAcoMMA)接枝在木材细胞壁上, 并且主要以无定形态存在。与未改性的木材相比, P(GMAcoMMA)/木材复合材料的静曲强度(MOR)、 尺寸稳定性、 防腐性能和热稳定性依次提高90.53%、 54.05%、 92.85%和31℃。      

熔融法制备EPDM-g-GMA及其与PBT的共混增韧

研究了EPDM－g-GMA对PBT的增韧作用及其增韧机理，在XSS－300转矩流变仪上根据自由基聚合通过熔融反应制备了EPDM－g-GMA 及其PBT／EPDM－g-GMA，用傅立叶变换红外光谱法考察接枝反应中特征官能团的存在，根据红外工作曲线测定了改性样品的接枝率，获得了共混物的冲击强度，在扫描电子显微镜下观察了共混物断面的微观形态，实验结果表明，当接枝共聚物的接枝率为2．3，分散相粒径在0．5μm左右时，共混物的冲击强度可达49．7kJ/m^2，比纯PBT提高了30倍，接枝共聚物的存在可以改善EPDM与PBT间的相容性，EPDM对工程塑料PBT的增韧作用是通过提高两相间的界面结合，增强界面粘结作用实现的。     

基于GMA的轻量级高性能计算环境监控

针对高性能计算环境监控的一般要求,分析对比现有的监控体系结构,设计了基于GMA体系结构的监控系统,详细介绍了设计中的几个关键问题,并给出了解决办法,最后实现了一个轻量级且高效的高性能计算环境作业监测系统。