Singlet oxygen generation and adhesive loss in stimuli‐responsive,fullerene‐polymer blends,containing polystyrene‐block‐polybutadiene‐block‐polystyrene and polystyrene‐block‐polyisoprene‐block‐polystyrene rubber‐based adhesives

The adhesive properties, as measured by bulk tack and peel strength analysis, were found to decrease in polystyrene‐block‐polybutadiene‐block‐polystyrene (SBS) and polystyrene‐block‐polyisoprene‐block‐polystyrene (SIS) PSA films containing common singlet oxygen generators, acridine, rose bengal, and C₆₀ fullerene, when irradiated with a tungsten halogen light in air. The addition of the singlet oxygen quencher, β‐carotene, to the C₆₀ fullerene samples was found to significantly deter the rate of adhesive loss in the fullerene‐SBS and ‐SIS PSA nanocomposites. The presence of oxygen was essential to the mechanism of adhesive loss and, in combination with the effects of singlet oxygen generators and a singlet oxygen scavenger, strongly supports a singlet‐oxygen mediated process. FTIR investigations of fullerene‐SBS and ‐SIS systems suggest the initial formation of peroxides which, upon further irradiation, lead to the generation of carbonyl‐containing compounds of a ketonic type after crosslinking. Rates of SBS and SIS C‐H abstraction were comparable and found to decrease when the high‐pressure, mercury xenon irradiation source was filtered to allow only light of λ > 390 nm. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Influence of diaminobenzoyl‐functionalized multiwalled carbon nanotubes on the nonisothermal curing kinetics,dynamic mechanical properties,and thermal conductivity of epoxy–anhydride composites

To obtain advanced materials with a high thermal dissipation, the addition of multiwalled carbon nanotubes containing diverse functionality groups, that is, as‐received multiwalled carbon nanotubes (AS‐MWCNTs) and diaminobenzoyl multiwalled carbon nanotubes (DA‐MWCNTs), to epoxy–anhydride composites was accomplished. According to nonisothermal differential scanning calorimetry analysis, the reactive functional groups present on the surfaces of the AS‐MWCNTs and DA‐MWCNTs accelerated the nucleophilic addition reaction of epoxy composites. Because of the difference in the reactivities of these functional groups toward epoxy groups, the distinction of fractional conversion and the reaction rate of the curing process were remarkably evident at the early stage. A suitable kinetic model was effectively elucidated with the Málek approach. The curing kinetics could best be described by a two‐parameter autocatalytic model as a truncated ?esták–Berggren model. The DA‐MWCNTs achieved effective load transfer and active heat conductive pathways; this resulted in good dynamic mechanical and thermal properties. As a result, the diglycidyl ether of bisphenol A/DA‐MWCNTs constituted an effective system with enhanced heat dissipation of materials for electronic applications. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43567.     

Effect of anhydride curing agents,imidazoles, and silver particle sizes on the electrical resistivity and thermal conductivity in the silver adhesives of LED devices

This study investigated the preparation of silver adhesives applied to a light‐emitting diode (LED) device as die‐attach materials consisting of silver particles, on epoxy resin, curing agents, and accelerants for complete curing at 150 °C for 30 min. For the epoxy resin, this study used 3,4‐epoxycyclohexyl‐methyl‐3,4‐epoxycyclohexanecarboxylate mixed with different types of anhydride curing agents such as 4‐methylcyclohexane‐1,2‐dicarboxylic anhydride and hexahydrophthalic anhydride as well as imidazole accelerants such as 2‐ethyl‐4‐methyl‐1H‐imidazole‐1‐propanenitrile, 2‐phenylimidazole, 2‐methylimidazole, 2‐phenyl‐2‐imidazoline, and 1,2‐dimethylimidazole. In addition, different size of silver particles and hybrid silver particles were used for the electrical resistivity and thermal conductivity of silver adhesives. Differential scanning calorimetric (DSC) measured conversion of silver adhesives based on different types and contents of the curing agents and accelerants under heating. The silver particles' distribution of silver adhesive also affected electrical resistance, as proved by scanning electronic microscopy (SEM) and four‐point probe. The obtained results showed that the silver adhesive containing an 100 wt % of epoxy resin mixed with 85 wt % of hexahydrophthalic anhydride, 1.0 wt % (weight of epoxy resin) of 2‐ethyl‐4‐methyl‐1H‐imidazole‐1‐propanenitrile, and 80 wt % (weight of epoxy resin) of hybrid silver particles (40 wt % 15 μm and 40 wt % 1.25 μm) was perfect, having the lowest electrical resistivity at 1.11 × 10^?4 Ω·cm and good thermal conductivity at 3.2 W/m·K. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43587.     

Preparation and properties of emulsifier/N‐methylpyrrolidone‐free crosslinkable waterborne polyurethane–acrylate emulsions for footwear adhesives. I. Effect of the acrylic monomer content

Stable emulsions of emulsifier/N‐methylpyrrolidone‐free crosslinkable waterborne polyurethane–acrylates (C‐WBPUAs) with various acrylic monomer contents (0, 10, 20, and 30 wt %) for footwear adhesive materials were successfully prepared in this study. The effects of the acrylic monomer content on the shelf stability, mean particle size, and viscosity of the C‐WBPUA emulsions; the tensile properties and dynamic mechanical thermal properties of the C‐WBPUA film samples; and the adhesive strengths between the upper (synthetic leather) and the sole (ethylene vinyl acetate rubber) in both the dry and wet states of the formulated adhesives (C‐WBPUA emulsion–thickener–hardener) were examined. The adhesive strengths of the formulated adhesives for footwear (leather–sole) in both the dry and wet states increased with increasing acrylic monomer content up to 20 wt %; after this, they almost levelled off. Thus, C‐WBPUA20 and C‐WBPUA30, where the number indicates the acrylic monomer content, can be recommended as high‐performance adhesive materials for footwear. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43758.     

In situ gelling ophthalmic drug delivery system: Formulation and evaluation

Designing a drug delivery system to target the eye is an interesting and challenging endeavor faced by scientists because of the critical and pharmacokinetically‐specific environment that exists in the eye. Topical administration of ophthalmic drugs is used to alleviate the symptoms and signs caused by ocular surface inflammatory disorders, to treat infections, for glaucoma or intraocular inflammation (uveitis). However, the responsiveness toward the conventionally developed drug delivery system is limited because of the presence of several types of barriers in the eye that impede the effective passage of many drugs leading to minimal dose absorption. Ion activated in situ gelling ocular systems undergo phase transition in the presence of cations (present in the tear fluid), thus enhancing the residence time of drug in the cornea. In the present study natural polysaccharides (pectin alone or in combination with sodium alginate) or a pectin derivative (thiolated pectin [TP] alone or in combination with sodium alginate) were used to formulate in situ gelling eye drops. The formulations were evaluated for their gelling capacity, rheological studies, spreadability, bioadhesion strength, and in vitro drug release. Thiolation of pectin was observed to result in an increase in the gelling behavior, viscosity, and bioadhesive strength. The formulations comprising pectin alone (P₇), combination of pectin and sodium alginate (P₅SA₁) or TP₆ demonstrated good in vitro release characteristics. The optimized formulations displayed a significant decrease in the intraocular pressure as compared to the marketed formulation upon instillation in rabbit eye. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39788.     

Relationship Between Viscoelastic and Peeling Properties of Model Adhesives. Part 2. The Interfacial Fracture Domains

The viscoelastic and peeling properties of polybutadiene/tackifying resin compatible blends have been studied in detail. Viscoelastic properties have been described through the variations of the complex shear modulus, G*(w), as a function of frequency, W, and peeling properties through the variations of peeling force (F) as a function of peeling rate (V).

The first paper of this series presented the cohesive fracture domain and the present paper explores the interfacial fracture domain: (i) rubbery interfacial (interfacial 1); (ii) stick-slip; (iii) glassy interfacial (interfacial 2). After a general survey of the properties in the three domains we present a quantitative relationship between the peeling and linear viscoelastic properties as a function of the adhesive formulation, discussing the use of time-temperature equivalence for adhesive properties. The third part of the paper presents the trumpet model of de Gennes describing the crack shape and propagation: starting from a mechanical analysis of the peeling test, it is shown how one may calculate the variations of the peeling force as a function of peeling rate in the various interfacial fracture domains: this model defines a single interfacial fracture criterion which coexists with the cohesive fracture criterion defined earlier, whatever the fracture location.

We present as a conclusion a critical discussion of the relevance and physical meaning of such a criterion and present a new outlook for the modeling and improvement of adhesive formulations.     

国内厌氧胶技术发展的一些动态

本文就国内厌氧胶的发展过程中,其中一些厌氧胶品种和所使用技术的情况与动态,进行扼要的介绍。     

超支化聚合物改性明胶胶粘剂的制备及性能

以二乙醇胺、丙烯酸甲酯、三羟甲基丙烷以及环氧氯丙烷为原料,合成不同代数的端环氧基超支化聚（胺-酯）(EHPAE)。其后,以从制革废弃物中提取的明胶为原料,不同代数的EHPAE分别作为交联单体进行改性,制得一种环保型鞋用或包袋用胶粘剂。采用FT-IR光谱,1H-NMR谱图和GPC对超支化聚合物和胶粘剂的结构及相对分子质量分布进行表征,之后对胶粘剂的粘接性能进行测定,结果表明：EHPAE-Ⅲ较其余两者的改性效果更为明显,当EHPAE-Ⅲ用量为明胶用量的30％时,改性后胶粘剂的固含量由11.42%提高到了30.33%,同时剪切强度为2.216 MPa,T-剥离强度为3.375 N/mm,水接触角为100.9o,相较于市售胶粘剂的剪切强度 (1.88 MPa),T-剥离强度 (2.864 N/mm),水接触角(84.8o),制备得到胶粘剂的粘接性能和疏水性均更优。     

木材工业胶黏剂的现状与未来

介绍了我国木材工业胶黏剂的应用概况,分析了国内外木材工业胶黏剂的研究进展,总结了木材工业胶黏剂的发展趋势,并针对我国木材工业胶黏剂发展过程中的主要问题,提出建议。     

大豆蛋白胶黏剂制备过程中的黏度变化及其黏合性研究

运用Brabender黏度仪研究改性大豆分离蛋白(SPI)胶黏剂制备过程中的黏度变化,并对它们的黏合性进行了研究.结果发现:改性SPI胶黏剂制备过程中的黏度变化趋势大致相同;制备过程中,改性SPI胶黏剂的起始黏度随NaOH浓度的增加而增加,由90BU增加到550 BU,而尿素、三聚磷酸钠、Na3PO4对其影响较小;0.7%(WNaOH/WSPI)NaOH改性SPI胶黏剂的黏合性较好,其T剥离强度为140.8 g/cm,比未改性SPI胶黏剂增加了61.8%.