Study of physico-mechanical properties of epoxy coatings modified with liquid rubbers with terminal carboxyl group

The effect of co-condensation products of low molecular weight carboxylated butadiene and butadienenitrile rubbers with epoxy resin ED-20 on physico-mechanical properties of epoxy-rubber coatings and free films was studied.     

Adjustment of properties of epoxide compositions cured with polyoxypropylene triamine

The effect of the temperature for mixing epoxy-diane resin ED-20 with a curing agent, specifically polyoxypropylene triamine, the ratio of the components, and the introduction of diluting agents and fillers on the strength properties and water absorption of cured compositions is investigated. It was shown that, by using these methods, one can affect the parameters of characteristics of epoxide compositions.     

Adsorption Modification of Dispersed Aluminum: Thermal Desorption Mass Spectrometry of the Modifying Layers

Thermal desorption and thermodestruction of modifiers (short- and long-chain aliphatic carboxylic acids, synthetic butadiene and nitrile rubbers with end carboxyl groups) were studied by thermal desorption mass spectrometry. The results obtained were compared with the thermal stability of individual modifiers. It was shown that the use of dispersed aluminum as a filler decreases the thermal stability of compositions based on butadiene and nitrile rubbers.     

The maximum superheating of butadiene rubber

The rates of thermal decomposition and maximum superheatings of butadiene rubber were measured by the contact thermal analysis method under the conditions of fast sample heating. The results are compared with the literature data on the products of the decomposition of butadiene rubbers of similar chemical compositions under flash pyrolysis conditions obtained by IR Fourier transform spectroscopy.     

Effect of modification with rubber on properties and process of curing of epoxy–rubber adhesive compositions

The effect of SKN-30KTRA low molecular weight rubber on the elastic and strength properties of adhesive compositions made with epoxy-rubber composition, is shown. The data on the effect of rubber on curing of adhesive compositions are presented.     

Properties and application of rubber-based sealants

Features of the chemical nature, physical state, hardening mechanism, application technology, properties, and main practical fields of application of sealing and tightening materials based on polysulfide and siloxane rubbers are considered. Brands of domestically produced polysulfide and silicon-organic sealants that gained the greatest distribution in engineering and construction are considered. Different technological sealant application methods used in production and repair of various types of machines and equipment are reviewed.     

Study of interfacial chemistry on direct curing adhesion between Ni–P plating and rubber using 1,3,5‐triazine‐2,4,6‐trithiol monosodium salt

Direct adhesion between Ni–P‐plated iron and acrylonitrile–butadiene rubber, hydrogenated acrylonitrile–butadiene rubber and ethylene–propylene rubber was successful using 1,3,5‐triazine‐2,4,6‐trithiol monosodium salt (TTN) without any adhesive. Peel strength in the adherends was influenced by the amount of TTN employed. The interfacial structure between Ni–P‐plated iron and curing rubbers has been investigated with x‐ray microanalysis, x‐ray photoelectron spectroscopy and scanning electron microscopy. The TTN derivatives gathered locally at the interface between the Ni–P‐plated iron and curing rubber adherends. The TTN layer located near the interface is referred to as a reinforcement layer. This layer was in general ～70 nm thick and consisted of composites of the Ni salt of TTN. The TTN is thought to work as a binder that bonds between Ni–P‐plated iron and rubber chains. The single bonds between both Ni–P‐plated iron and rubber TTN was confirmed from Kraus plots and model experiments using TTN. Copyright © 2003 John Wiley & Sons, Ltd.     

Derivatives of carbamide, symmetrical triazines, and heptazines: Ecologically clean fire retardants for different thermostable compositions

The problems of replacing conventional halogen-containing fire retardants with alternative products, such as carbamide and symmetrical triazines and heptazines obtained on its basis, as well as different phosphates and ammonium polyphosphates, are considered. The main properties of the suggested compounds are described. It is shown that the range of compounds can be used, not only as fire retardants, but also as curing or modifying agents for polymer compositions, thermostabilizers of resins (based on ethylene-propylene rubbers) and sealants, and components of thermostable organosilicon compositions.     

Investigation of epoxide adhesive compositions cured with polyoxypropylene triamine

The results of investigations of the effect of Jeffamine-type curing agents on the adhesion and physicomechanical properties of epoxide compositions modified with rubber are presented. It was shown that epoxy-rnbber oligomers cured with polyoxypropylene tria mine are characterized by high elasticity with good cohesion and adhesion strength, which allows one to obtain adhesive compositions with small quantities of internal stresses on their basis that can be used at negative temperatures under the conditions of dynamic loads and thermal cycles.     

Modification of polychloroprene-based adhesive compositions with nitrogen-containing compounds

The possibility of improving the adhesive characteristics of polychloroprene-based adhesive compositions by modifying them with nitrogen-containing adhesion promoters was studied. It was shown that the modification of polychloroprene with microquantities of nitrogen-containing compounds results in an increase in the durability of the glue fastening of rubbers based on different caoutchoucs by an average of 0.5–3.5 times.     

Thermal properties of diene elastomers

The paper presents the results of investigating the effect of the macromolecule chemical structure and the spatial network structure of butadiene (BR), butadiene-styrene (SBR) and butadiene-acrylonitrile (NBR) rubbers on their thermal properties. The rubbers were cross-linked by the conventional method by means of dicumyl peroxide or sulfur as well as by the non-conventional way using iodoform (CH₃I). The rubber and their vulcanizates were assessed by the derivatographic method (under air) and by means of differential scanning calorimetry (DSC) under inert gas. The thermal cross-linking degree of the polydienes and the efficiency of the cross-linking processes, dependent on both the chemical structure of elastomer macromolecules and their spatial network structure were determined. The cross-linking of elastomers with iodoform changes the thermal properties of polymers, significantly increasing their glass transition temperature during both sample heating and cooling, which results from the increase in mutual interaction of macromolecules connected with their modification with iodine compounds.     

Effect of chitosan derivatives as rubber antioxidants for increasing durability

A series of chitosan derivatives, namely polydiethylamino-ethylmethacrylate-chitosan-graft-copolymer (chitosan-g-DEAEMA), polycarboxy-chitosan-graft copolymer (chitosan-g-COOH), polyvinyl alcohol chitosan-graft-copolymer (chitosan-g-VOH), and carboxymethyl-chitosan (CM-chitosan), were synthesized and investigated as antioxidants for natural rubber (NR) and acrylonitrile butadiene rubber (NBR) mixes and vulcanizates to increase their durability. The rheometric characteristics of the rubber mixes were determined using an oscillating disc rheometer. The physico-mechanical properties of the rubber vulcanized were measured before and after exposure to thermal oxidative aging. It was found that the CM-chitosan had an accelerating effect on the curing process of NR and NBR. Also, the investigated polymers enhanced the properties of rubbers (NR and NBR) especially after ageing up to 7 days compared with commercial antioxidants, such as phenyl ß-naphthylamine (PßN) and N-isopropel-Nphenyl-p-phenylene diamine (IPPD) which are used in the rubber industry. After ageing, the retained values of tensile strength, modulus at 100 % strain, and elongation at break were improved. The optimum concentration of the investigated compounds used to give good properties was found to be 1–2 parts per 100 of rubber (phr). In addition, these prepared polymers showed a decrease in the equilibrium swelling of rubber in toluene which is the proper solvent and consequently increases the crosslink density for rubbers.     

Effects of curing agents and modified graphene oxide on the properties of XNBR composites

This paper investigates the effects of crosslinking methods on the incorporation of graphene oxide (GO) in carboxylated nitrile butadiene rubber (XNBR) in the process of producing nanocomposites for chemical-resistant protective clothing and gloves. The novel aspect of the study is a comprehensive approach involving both unmodified GO as well as GO that was carboxylated to increase its affinity to XNBR and to facilitate its application. The nanostructure of XNBR composites was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Fourier transform infrared spectroscopy (FTIR) was used to elucidate the chemical structure of the composites. Thermal stability studies were performed using differential scanning calorimetry (DSC). The barrier properties of the composites were determined based on swelling, crosslinking density, and permeation by mineral oils. The mechanical tests included resistance to puncture and abrasion, stress at strain, and tensile strength. Contact angle was measured to determine the degree of hydrophobicity of the obtained composites.AFM and SEM images revealed the effects of different curing agents (sulfur, magnesium oxide, or a hybrid system) as well as GO type on the surface morphology of XNBR composites. The type of curing agent was found to affect the kind of crosslinks formed and their spatial network structure, as confirmed by FTIR. The DSC curves showed that the crosslinking methods of XNBR did not affect glass transition temperature, but led to large changes observed in the temperature range of 130–220 °C.The type of crosslinking method affected the degree of swelling. It was found that the incorporation of carbon nanofillers led to an improvement in the abrasion and puncture resistance as well as tensile strength of XNBR composites. The water contact angle of the composites indicated hydrophobicity. The properties of XNBR composites containing GO revealed their substantial application potential in protective clothing.     

Modern synthetic adhesives based on epoxy-rubber compositions

Results of investigations of adhesives and compounds based on epoxy resins modified with low-molecular rubbers are presented. A series of epoxy-rubber compositions with improved physicomechanical characteristics and operational properties are developed. Examples of solutions of engineering challenges using high-molecular synthetic adhesive systems are given.     

Influence of modified biopolymers on thermal properties and biodegradation processes of carboxylated nitrile-butadiene (XNBR) nanocomposities

Journal of Thermal Analysis and Calorimetry - The presented study includes a comparison of the effect of fillers used in carboxylated nitrile butadiene rubber XNBR on the properties of the obtained...     

Experimental branching results for diene polymers by use of gel-permeation chromatography

Branching analyses in styrene–butadiene rubbers and polybutadiene rubbers have revealed large differences in branching between rubbers polymerized in different ways. The functionalities of several star-branched solution-polymerized styrene–butadiene rubbers were calculated and compared to their expected structures. Emulsion-polymerized polybutadiene rubber and a series of solution-polymerized polybutadienes made with different catalysts had different degrees of random branching, and evidence is presented indicating that the different available catalyst systems provide some latitude in making rubbers of different branching contents. Random branching analyses on a series of emulsion-polymerized styrene–butadiene rubbers revealed the dependency of branching on molecular weight and molecular weight distribution. The influence of polymerization temperature on the branching of emulsion-polymerized styrene–butadiene rubber was also studied.     

丁苯橡胶/天然橡胶复合体系动态力学性能

生热;动态力学损耗;丁苯橡胶/天然橡胶复合体系动态力学性能     

Adhesive compositions based on perchlorovinyl resin with enhanced adhesion to polymeric elastic materials

A possibility of modifying the adhesive compositions based on perchlorovinyl resin with amino-containing compounds is studied. Aniline and N-nitrosodiphenylamine were used as amino-containing adhesion promoters. It is shown that, at an optimal content of an adhesion promoter, ED-20 resin, and plasticizer additives in the gluing composition, the bond strength of vulcanized resins based on different rubbers and linoleum increases by 1.7–3.3 times.     

Modification of Phenol- and Carbamide-Formaldehyde Resins by Cellulose By-products

To improve their properties, phenol- and carbamide-formaldehyde adhesives were modified by cellulose by-products. It has been shown that the introduction of pectol into phenol-formaldehyde resin of SFZh-3013 grade and products of sulfite-cellulose production into adhesive compositions based on carbamide-formaldehyde resins increases the plywood gluing strength and curing rate.     

Novel polysulfide sealing compositions for aircraft industry

A composition of fullerene-type materials with components of VITEF-1 and U-30MES-5 polysulfide sealing materials was developed that enabled their modification by additives of fullerenes, carbon nanotubes, and astralens. The insertion of these nanomodifiers was proven to significantly improve the physicochemical, mechanical and adhesive parameters of elaborated compositions. The mechanistic basis for the observed affect of fullerene-type additives on the properties of polysulfide sealings was also discussed. In the study, a variety of fullerenes developed at the Institute Of Chemical Physics Problems, Russian Academy of Sciences was tested. The species fullerene-modified were modified by the incorporation of organic radicals with functional amine, polycarboxyl, and hydroxyl groups that enabled their predetermined implementation into polymer molecules. The resulting pilot batches of polysulfide sealing agents based on additives were found to demonstrate longer shelf lives and greater adhesion strength in comparison to the known industrial samples.