Effects of Alcell Lignin Methylolation and Lignin Adding Stage on Lignin-Based Phenolic Adhesives

To investigate the effects of lignin methylolation and lignin adding stage on the resulted lignin-based phenolic adhesives, Alcell lignin activated with NaOH (AL) or methylolation (ML) was integrated into the phenolic adhesives system by replacing phenol at various adhesive synthesis stages or directly co-polymerizing with phenolic adhesives. Lignin integration into phenolic adhesives greatly increased the viscosity of the resultant adhesives, regardless of lignin methylolation or adding stage. ML introduction at the second stage of adhesive synthesis led to much bigger viscosity than ML or AL introduction into phenolic adhesives at any other stages. Lignin methylolation and lignin adding stage did not affect the thermal stability of lignin based phenolic adhesives, even though lignin-based adhesives were less thermally stable than NPF. Typical three-stage degradation characteristics were also observed on all the lignin-based phenolic adhesives. Three-ply plywoods can be successfully laminated with lignin based adhesives, and it was interesting that after 3 h of cooking in boiling water, the plywoods specimens bonded with lignin-based phenolic adhesives displayed higher bonding strength than the corresponding dry strength obtained after direct conditioning at 20 °C and 65% RH. Compared with NPF, lignin introduction significantly reduced the bonding strength of lignin based phenolic adhesives when applied for plywood lamination. However, no significant variation of bonding strength was detected among the lignin based phenolic adhesives, regardless of lignin methylolation or adding stages.     

Advances in the development of adhesives and technologies for manufacturing mechanical rubber parts of aircraft

The paper describes new developments by the All-Russian Scientific Research Institute of Aviation Materials in the field of mechanical rubber adhesives and technologies for their use in aeronautical engineering. The basic properties of cold-setting rubber adhesives and adhesives designed for bonding rubbers with metals in the process of vulcanization are given. The advantages of the new adhesives relative to existing adhesives or those used previously are shown.     

Cement-polymer adhesive materials

Tile adhesives consisting of Portland cement, fillers, water, and polymer admixtures are described. The key components of tile adhesives are considered. Special attention is paid to polymer components of these adhesives. Information on the largest manufacturers of tile adhesives in Russia is given.     

Adhesives and compounds in manufacture of electronic mechanisms

The general properties of adhesives and compounds for electronic articles are described that were elaborated by the company: TK-1 adhesive with elevated thermal conductivity; TEK-type adhesives that demonstrate higher elasticity and adhesion ability; TK-8-type all-purpose adhesives; MS-type, single-packed, thermally stable glues for long storage; electrically conductive adhesives; TPK-1 and TPK-2 magnetic adhesives and TPK-3 nonmagnetic adhesive; and some compounds, e.g., epoxide molding compositions. The functionality of all adhesives and compounds presented were tested for weather factors, including elevated humidity, higher and lower temperatures, thermal cycles, effects of vibrations for both pilot samples, and final articles of electronic mechanisms.     

Investigations of protein casein adhesives in 1927–1934 in research works of Central Aerohydrodynamic Institute and All-Russia Institute of the Aircraft Materials

An initial study of the adhesives in the Soviet Union aimed at the application of adhesives in air-craft engineering is presented. A general concept of the adhesives in 1920 is given, the assortment of the zoogenic protein adhesives is presented, and the manufacturing procedure of the latter is outlined. Detailed information on the results of the first scientific-research works in the country in the field of the adhesives carried out at the Department of the Research of the Aircraft Materials of the Central Aerohydrodynamic Institute (TsAGI) is presented. It has been found that the fundamental study of the adhesives in our country arose due to the development of domestic wooden aviation and the manufacturing of airplanes from wood.     

Adhesive joints used in IL-series aircrafts

The technological and strength characteristics of adhesives used in honeycomb and layer-built structures, as well as the performances of adhesives for structural applications, are given. All adhesives are used in the structures of aircrafts of Il series. The fields of adhesives application in the structure of aircrafts of Il series are described.     

Investigations of zoogenic protein adhesives used for domestic aircraft engineering prior to 1930

An initial study of the adhesives in the Soviet Union aimed at the application of adhesives in air-craft engineering is presented. A general concept of the adhesives in 1920 is given, the assortment of the zoogenic protein adhesives is presented, and the manufacturing procedure of the latter is outlined. Detailed information on the results of the first scientific-research works in the country in the field of the adhesives carried out at the Department of the Research of the Aircraft Materials of the Central Aerohydrodynamic Institute (TsAGI) is presented. It has been found that the fundamental study of the adhesives in our country arose due to the development of domestic wooden aviation and the manufacturing of airplanes from wood.     

Investigation of Degradation of Structural Adhesives under Influence of Chemicals

Structural adhesives are used for joining materials also under conditions, where they through the application will be influenced by many different chemicals. The adhesives can – if not protected from the chemical influence – be degradated of the chemicals. The degradation can because of the different structures of the polymers in the adhesives result in lower strength of the joining area, but can also give higher strength but brittleness. Information of the structures of the structural adhesives used in the project have been taken from the data sheets from the manufacturers and have been compared with investigation of the structures by FTIR and DSC. In the laboratory the HSP's (Hansen Solubility Parameters) of the adhesives has been determined and compared with the theoretically estimated HSP's. The estimation has mainly been done by Lydersens group contribution method. The chemical resistance of the adhesives have been foreseen by using HSP's of the adheisves and compared them with the HSP's of the chemicals. The structural adhesives were most of the epoxy types and of the polyurethane types with different curing systems. The structural adhesives should all have high strength and an opening time of more than 30 minutes. They were in the laboratory cured up after the specifications from the manufacturer and were stored one week after curing before they were influenced by hte chosen chemicals. The chemicals were chosen from their functional groups. In the laboratory the adhesives were influenced by different chemicals at room temperarture and under elevated temperature and under different periods to develope the degradation curves for the different chemicals and to foresee the degradation time of the adhesives before their properties were not acceptable any more. The structure after influence of the chemicals is studied by FTIR. The results of the investigations have been that it is possible to estimate the degradation by using the HSP's of the adhesives and the chemicals, but to estimate the time before degradation has been so serious that the properties of the adhesives are not acceptable any more, it is necessary to add laboratory investigations to the HSP comparisons of adhesives and chemicals. The comparison of the HSP and of the chemicals by which the adhesives can be in its lifetime has seen to be usefull especially if the chemicals are pesticides.     

高分子材料类专业胶粘剂课程教学探析

从我国胶粘剂产业的快速发展对专业技术人才的需求出发,提出了在高等学校的高分子材料类专业中开设胶粘剂课程的重要性,介绍了胶粘剂课程具有多学科高度交叉并集理论性、实践性和应用性于一体的教学特点,并结合近几年胶粘剂行业发展的新情况和我们在胶粘剂课程中的教学经验,总结了在讲授过程中的教学体会和教学方法,认为通过抓住课程特点和明确主线、灵活运用多媒体教学手段、增加实践性教学环节以及注重教学效果反馈等手段和措施,可以有效提高该类课程的教学质量。     

氢键作用驱动原花青素构筑水基抗菌黏合剂北大核心CSCD

水下黏合剂在生物医学和工程应用领域的需求越来越大。然而,目前报道的大多数水下黏合剂的制备方法中通常需要复杂的化学偶联或修饰,以及昂贵的构筑基元。本文利用低成本的葡萄籽提取物原花青素(PA)和商业化的聚乙二醇寡聚物(PEG)为构筑基元,发展了一种简单且经济的水下黏合剂的构筑策略,实现了在氢键作用下诱导仿生黏合剂生成。此黏合剂既可以在水上又可以在水下黏附不同材质的基底,且可重复使用。此外,易于制备的PA/PEG黏合剂也具有良好的抗菌活性和生物相容性。由于PA/PEG黏合剂具有制备简单、广谱黏附性、可循环使用和抗菌性等优点,将在医疗器械和制药应用中得到广泛应用。     

Contact adhesives based on polyurethanes and natural rubbers

A review of the chemistry, technology, properties, and range of application of contact polyurethane adhesives, as well as adhesives based on natural rubber, is presented. The main types of adhesives produced by the Anles corporation are described.     

Properties of adhesives and adhesive materials used in aviation industry

Methods for developing adhesives and adhesive material used in the structures of almost all units of aviation machinery are described step by step. The properties of high-strength film-forming adhesives; adhesive prepregs; sandwich-type aluminum-polymer materials (SIALs); cold- and hot-setting adhesives intended for gluing metals, different nonmetallic materials, and combined joints; and self-adhesive film materials of ZPPK and FAS grades are given. It is also shown where and for which purposes these adhesives are applied.     

Hydrogel adhesives for generalized wound treatment: Design and applications

Wound refers to the place where human body is injured and ruptured. So, wounds in a broad sense include not only skin wounds, but also damages of muscle, corneal, heart, and lung, etc. As “gold standard” of wound closure, suture and staple cause secondary damage to the tissue, and require professional skills and equipment, so noninvasive hydrogel adhesives have been developed as an alternative to close and treat different kinds of wounds. However, the existing reviews mainly discussed the research of hydrogel adhesives for skin wounds, and the focus is mostly on its types and adhesion mechanisms, but a review comprehensively discusses the design and application of hydrogel adhesives on generalized wounds for wound closure and wound healing and the unique needs of various wounds for hydrogel adhesives is still lacking. In this review, the types and adhesion mechanisms of hydrogel adhesives will be briefly described, then the research progress of hydrogel adhesives in wound treatment is reviewed in detail from two aspects: the comprehensive design principles and the unique requirements of different types of wounds. Overall, we expect that this review will provide guidance for the development of hydrogel adhesives as new avenues for generalized wound care and treatment.     

Adhesives and sealants based on sulfur

Examples of applications of adhesives and sealants based on sulfur as a main component are presented. Prospective applications of sulfur as a cheap and available raw material for adhesives are shown. The basic formulations of sulfuric adhesives and the approximate technology of their production and application are described.     

New trends in creation of epoxy adhesives

Modern trends in development of production of epoxy adhesives with the purpose of obtaining high-strength, waterproof, and high-temperature adhesives are described. Such adhesives are developed and manufactured at ZAO ENPTs EPITAL based on the epoxy-diane and cycloalphatic epoxy resins. The modified aromatic amines, aromatic polyaminoamides, alkylamino phenols, as well as original curing systems are used as curing agents.     

POSS-modified PEG adhesives for wound closure

PEG-related adhesives are limited in clinical use because they are easy to swell and cannot support the cell growth.In this study,we produced a series of POSS-modified PEG adhesives with high adhesive strength.Introduction of inorganic hydrophobic POSS units decreased the swelling of the adhesives and enhanced cell adhesion and growth.The in vitro cytotoxicity and in vivo inflammatory response experiments clearly demonstrated that the adhesives were nontoxic and possessed excellent biocompatibility.Compared with the sutured wounds,the adhesive-treated wounds showed an accelerated healing process in wounded skin model of the Bama miniature pig,demonstrating that the POSS-modified PEG adhesive is a promising candidate for wound closure.     

木质素活化及在木材胶粘剂中的应用进展

木质素是相对分子量较高的天然聚合物,由于具有苯酚结构利于制备木材胶粘剂,但是木质素本身反应活性低,一般都将其活化后再利用.而且,除了以往利用最多的造纸工业产生的木质素外,研究发现木材经过褐腐菌降解后残留主要成分是结构部分发生变化的木质素,这种可再生生物质资源以其自身的结构特点在合成胶粘剂上也有很大的优势,本文结合木质素胶粘剂应用中的问题,重点概述了活化木质素的各种方法及褐腐木质素在木材胶粘剂中的应用.     

Contribution of relaxation processes to adhesive-joint strength of viscoelastic polymers

Relaxation processes accompany all stages of the lifetime of viscoelastic pressure-sensitive polymer adhesives, which can form strong adhesive joints with substrates of various chemical natures under application of a slight external pressure to the adhesive film for a few seconds. This review deals with comparison of the adhesion and relaxation properties of a number of typical pressure-sensitive adhesives based on polyisobutylene, butyl rubber, styrene-isoprene-styrene triblock copolymers, alkyl acrylate copolymers, and silicone adhesives as well as pressure-sensitive adhesives based on blends of high-molecular-mass polyvinylpyrrolidone with oligomeric poly(ethylene glycol). Within all three stages of the lifetime of adhesive joints (under adhesive-bond-forming pressure, upon withdrawal of contact pressure in the course of relaxation of the adhesive material, and under the force detaching an adhesive film from the substrate surface), the strength of adhesive joints has been shown to be controlled by large-scale relaxation processes, which are characterized by long relaxation times in the range 150–800 s. All examined pressure-sensitive adhesives can be arbitrarily divided into two groups. The first group is composed of fluid adhesives that relax comparatively fast and exhibit no residual (unrelaxed) stress. The second group includes elastic adhesives capable storing mechanical energy in the course of deformation that are characterized by appreciably longer relaxation times and display residual stress after relaxation. Conditions of adhesive debonding (e.g., strain amplitude and deformation velocity) significantly affect the relaxation process.     

Investigation of artificial resin-based adhesives in works carried out by the all-Russia Scientific Research Institute of Aviation Materials in 1936–1937

The main preconditions for developing principally new (for the examined period of time) adhesives based on artificial resins are presented. The results of application of the combined (casein and resin) adhesives, adhesives based on novolak, karbolit and barite phenol formaldehyde resins are given. It is shown that the phenol-barite resin of VIAM-6 grade was the most suitable for the aviation industry at that time.