Windshield recycling focused on effective separation of PVB sheet

The study is focused on windshield recycling process resulting in poly(vinyl butyral) (PVB) sheets with very low amout of remain glass particles. PVB sheets were obtained from worldwide manufacturer DuPont and then they were laminated by standard autoclaving process. One sample of PVB sheet was modified by multi‐functional organic acid in order to compare various levels of adhesion. Three‐stage technology was proposed for recycling PVB sheets. In the first‐stage laminated safety glass was mechanically cracked. In the second‐stage the adhesion reduction to minimal degree was followed by chemical‐physical assisted separation. It causes self‐release of the glass out of the PVB sheet. The third‐stage was mechanical peeling of the remaining glass from the PVB sheet which completed the recycling process. The optimal process conditions for the most effective delamination process were found. Delamination technology produces PVB sheet with minimal residual glass content (up to 300 ppm) and minimal change in PVB sheet properties. Described recycling technology is ecologically friendly (the effluent is fully recyclable as well) and could reduce the worldwide problem with windshield waste disposal. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39879.     

Viscoelastic and adhesive properties of single‐component thermo‐resistant acrylic pressure sensitive adhesives

Poly(butyl acrylate‐vinyl acetate‐acrylic acid) based acrylic pressure sensitive adhesives (PSAs) were synthesized by solution polymerization for the fabrication of high performance pressure sensitive adhesive tapes. The synthesized PSAs have high shear strength and can be peeled off substrate without residues on the substrate at temperature up to 150°C. The PSAs synthesized in the present work are single‐component crosslinked and they can be used directly once synthesized, which is convenient for real applications compared to commercial multi‐component adhesives. The results demonstrated that the viscosity of the PSAs remained stable during prolonged storage. The effects of the preparation conditions such as initiator concentration, cross‐linker amount, organosiloxane monomer amount and tackifier resin on the polymer properties, such as glass transition temperature (T_g), molecular weight (M_w), surface energy and shear modulus, were studied, and the dependence of the adhesive properties on the polymer properties were also investigated. Crosslinking reactions showed a great improvement in the shear strength at high temperature. The addition of tackifier resin made peel strength increase compared to original PSAs because of the improvement of the adhesion strength. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40086.     

Development and evaluation of pressure sensitive adhesives from a fatty ester

Novel pressure sensitive adhesives (PSAs) were developed from renewable methyl oleate (MO) and fully evaluated for their peel strength, tack force and shear resistance. MO was epoxidized and selectively hydrolyzed on the ester group to form epoxidized oleic acid (EOA) that is a bifunctional monomer containing both a carboxylic acid group and an epoxy group. EOA was step‐growth polymerized to form a hydroxyl‐containing polyester, which was then cured in the presence of a small amount of a polyfunctional epoxide [epoxidized soybean oil or trimethylolpropane triglycidyl ether (TMPTGE)] to afford PSAs. The PSAs from the polyester cured with TMPTGE exhibited high peel strength (2.4 N/10 mm), high tack force (5.8 N), and sufficient shear resistance (9.0 min). The PSAs can be fully based on renewable natural materials, and their preparations are environmentally friendly. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41143.     

Bio‐oil from whole‐tree feedstock in resol‐type phenolic resins

Renewable chemicals are of growing importance in terms of opportunities for environmental concerns over fossil‐based chemicals. Lignocellulosic biomass can be converted into energy and chemicals via thermal and biological processes. Among all the transformation processes available, fast pyrolysis is the only one to produce a high yield of a liquid‐phase product called bio‐oil or pyrolysis oil. Bio‐oil is considered to be a promising substitute for phenol in phenol formaldehyde (PF) resin synthesis. In this work, bio‐based phenolic resins have been formulated, partially substituting phenol by bio‐oils from two Canadian whole‐tree species. The new resins are produced by replacing 25, 50, and 75% of phenol with bio‐oil for each species (three bioresins per species). The aim of this study is to synthesize renewable resins with competitive price and satisfactory quality. The results obtained have shown that substitution degree up to 50% provided reactivity and performance equal or superior to the pure PF resin. They also present a good storage stability, improved shear strength, and thermal stability comparable to the pure PF. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 40014.     

原位法制备不同形貌纳米银导电胶

采用原位一步法制备导电胶,通过改变实验工艺条件,研究了聚乙烯吡咯烷酮含量、超声分散时间、微波加热时间对导电胶性能的影响。通过TEM对产物形貌进行表征,并分析了不同条件对纳米银形貌的影响。当PVP为0.2 g、超声分散时间8 min、微波加热时间6 min时,制备的纳米银的尺寸4均一,导电胶的体积电阻率可达到3.56×10Ω·cm,可替代传统的锡铅焊料。     

纸板类儿童卡书抗弯曲性能影响因素研究

文章针对四种制备儿童卡书的卡纸进行研究,分析了卡纸纤维结构类型和表面粗糙度对儿童卡书变形度的影响。对水性胶粘剂固含量与儿童卡书弯曲度的关系研究发现胶粘剂固含量在60%~65%时,制备的卡书抗弯曲性能较好。此外,研究发现后处理环境条件选用温度23±3℃,湿度50±5%的标准条件,后处理时间为1个月左右得到的儿童卡书的弯曲变形度最小。     

填充碳纳米管各向同性导电胶的性能

制备了以碳纳米管(CNTs) 和镀银碳纳米管(SCCNTs) 为导电填料的各向同性导电胶, 研究了它们的电学性能、力学性能及抗老化性能, 并与传统的以微米量级的银粒子作为导电填料的导电胶的性能进行比较。研究发现: CNTs 作为导电填料时, 在填料体积分数为31 %时出现体积电阻率的最低值2. 4 ×10-3Ω·cm; 在填料体积分数为23 %时导电胶表现出最好的抗剪切性能。在填料体积分数同为28 %时, 填充SCCNTs 导电胶具有最低的体积电阻率2. 2 ×10-4Ω·cm; 填充CNTs 和SCCNTs 显示出比填充微米量级银粒子导电胶高的抗剪切强度(19. 6 MPa) 。在85 ℃、RH 85 %环境下经过1000h 老化测试结果表明: 填充SCCNTs 或CNTs 导电胶体积电阻率的变化和剪切强度的变化均不超过10 %; 而填充微米量级银粒子导电胶在老化后体积电阻率的变化和抗剪切强度的变化分别达到350 %和120 %。      

填充银纳米线各向同性导电胶的性能

以Ti (OC₄H₉)₄ 水解形成的溶胶体系为模板, 以AgNO₃ 为银纳米线的前驱体, 低温下合成长径比为50～60 的银纳米线, 采用TEM 和XRD 对所制得的银纳米线进行表征。以银纳米线作为导电胶的导电填料, 成功制备了一种高电导率的各向同性导电胶。导电胶的电学性能和力学性能测试表明: 这种导电胶在导电填料含量为56 wt %时的电导率比填充75 wt %微米银粒子的导电胶高约6 倍(体积电阻率为1. 2 ×10-4Ω·cm) 。由于填料含量的降低, 该导电胶的抗剪切强度(以Al 为基板时的抗剪切强度为17. 6 MPa) 相比于填充75 wt %微米银粒子和75 wt %纳米银粒子导电胶均有不同程度的提高。      

耐热型纸吸管纸的制备及性能研究

以漂白硫酸盐针叶木浆和阔叶木浆为原料,通过湿法成形、表面施胶及涂布耐热胶黏剂制备耐热型纸吸管纸,主要采用挺度、环压强度、湿抗张强度及接触角等指标评价纸吸管纸性能;对比探究了耐热胶黏剂与普通胶黏剂对纸吸管性能及使用安全性的影响。结果表明,CW/AKD混合乳液施胶量为14 g/m²,AKD用量为0.10%（相对于原纸定量,其中里纸定量100～140 g/m²,面纸定量40～80 g/m²）时,纸吸管里纸、面纸挺度分别为3.59 mN·m和2.63 mN·m,环压强度分别为1.75 kN/m和0.37 kN/m,抗张强度分别为7.68 kN/m和3.57 kN/m,湿抗张强度分别为1.43 kN/m和0.78 kN/m,吸收性分别为29.8 g/m²和27.2 g/m²,接触角分别达到145.9°和149.4°;热水抽出物含量分别为3.252%和3.312%,浸泡液浊度均在2 NTU左右;耐热胶黏剂不仅具有普通胶黏剂一样的黏合强度,且耐热、不溶于水,可用于耐热型纸吸管纸的黏合,且满足耐热型纸吸管纸的使用安全性能要求。     

Geometrical study of mixed adhesive joints for high-temperature applications

The use of adhesives for high-performance structural applications has significantly increased in the last decades. However, the use of adhesive joints in adverse environmental conditions is still limited due to the reduced capability of adhesives to withstand large thermal gradients. Dual adhesive joints, which contain two adhesives with remarkably different mechanical behaviours, are a technique suitable for being used in extreme temperatures. The object of this study is a ceramic–metal joint, representative of the thermal protection systems of some aerospace vehicles. In this paper, several joint-mixed joint geometries are presented, studied with recourse to finite element analysis. In a first phase, the three-dimensional finite element models and the material properties are validated against experimental data. In a second phase, the model geometry is modified, with the aim of understanding the effect of several changes in the joints’ mechanical behaviour and comparing the merits of each geometry. The models’ presented good agreement was found between experimental and numerical data and the alternative geometries allowed the introduction of additional flexibility on the joint but at the cost of lower failure load.