Road asphalt modifiers based on oil-resistant rubbers and products of thermal transformations of coals

The properties of asphalt binder modifiers prepared by dissolving butadiene-acrylonitrile rubbers and their production waste in liquid products of heat treatment of various brands of coal were studied.     

Toughening of highly cross-linked polycyanurates with epoxy- and phenol-terminated butadiene-acrylonitrile rubbers

Polycyanurate from dicyanate of bisphenol A was modified with epoxy- and phenol-terminated butadiene-acrylonitrile rubbers. Rubber-resincopolymerisation was followed by multiple-detection gel-permeation chromatography (GPC). It was found that both the epoxy-terminated and phenol-terminated rubbers react with the cyanate and thus are covalently bound with the polycyanurate network. The influence of rubber content, acrylonitrile content and type of end group on phase structure was investigated using dynamic mechanical analysis. Fracture toughness was measured for these modifications.     

Influence of carbon black on thermal properties and flammability of cross-linked elastomers

The paper presents the results of testing thermal properties and combustibility of butadiene-acrylonitrile rubber vulcanizates with different contents of bounded acrylonitrile: Perbunan NT 1845 and Perbunan NT 3945 from Bayer. The rubbers were cross-linked by means of dicumyl peroxide. Four types of carbon black with different specific surfaces were used as fillers. The test results were obtained with the use the derivatograph, DSC-204 of Netzsch, measurements of flammability by the method of oxygen index and in air. The results of measurements have shown that the thermal stability and flammability of the vulcanizates under investigation are affected by the activity of solid phase and the degree of surface development as well as the flexibility of polymeric chain and the degree of its unsaturation. A clear relationship has been found between the thermal properties and flammability of the cross-linked butadiene-acrylonitrile rubbers.     

Ozone resistance of crosslinked blends of butadiene-acrylonitrile and ethylene-propylene-diene elastomers and interphase interaction in these blends

The relation of ozone resistance to the volume and structure of the interphase layer and the amounts of crosslinks in the interlayer was studied for covulcanizates of butadiene-acrylonitrile rubbers of various polarities with ethylene-propylene-diene (EPDM) elastomers that differed in the comonomer composition and stereoregularity of propylene units. It was shown that the ozone resistance is determined by the compatibility of the components, the interlayer volume and density, the amount of crosslinks in the interlayer, and the strength of the EPDM network.     

Formation of an interfacial layer in blends of elastomers with different polarities

On the basis of experimentally measured deviations of the equilibrium degree of swelling in n-heptane from the additive value calculated for crosslinked heterophase blends composed of butadiene-acrylonitrile rubbers of different polarities and ethylene-propylene-diene terpolymers of the known comonomer composition and stereoregularity of propylene units, the density of interfacial layer and the amount of chemical crosslinks in it have been characterized. The effects of isomers of butadiene units, the ratio of comonomers in ethylene-propylene-diene terpolymers, and the degree of isotacticity of propylene units in the layer on the intensity of interfacial interaction in covulcanizates have been analyzed.     

Flammability of diene rubbers

This paper presents the results of testing the flammability and fire hazard of butadiene (BR), butadiene-acrylonitrile (NBR) and butadiene- styrene (SBR) rubbers with the use of oxygen index test, ignition temperature measurement, cone calorimetry and inverse liquid chromatography. Toxicometric indices, RTFH _CO/CO2, W_LC50SM and the concentration of polycyclic aromatic hydrocarbons (PAH) have been determined. The results obtained have been interpreted from the point of view of the chemical constitution of the polymers tested.     

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.     

Study of Properties of Film Materials Based on Cellulose and Polyurethane Rubbers for Drainage of Oils

Russian Journal of Applied Chemistry - The use of both cellulose and polyurethane rubbers of the PU-8TB and PU-8A grades is discussed in the work to create film materials for draining oils. By the...     

Thermal stability and flammability of butadiene- acrylonitrile rubber cross-linked with iodoform

Summary The paper discusses the results of thermal analysis and flammability of butadiene-acrylonitrile rubber, Perbunan NT 1845 of Bayer, cross-linked with iodoform. The properties of the iodoform vulcanizate have been compared with those of peroxide vulcanizate. The thermal analysis has been performed in air with use of a derivatograph under air and nitrogen atmosphere as well as dynamic scanning calorimetry (DSC). The flammability of vulcanizates has been determined by the method of oxygen index and in air. The toxicity of the thermal decomposition and combustion products of the vulcanizates under investigation has been also determined. Based on complementary examinations, DTA and DSC curves have been interpreted from the point of view of thermal transitions of the conventionally and non-conventionally cross-linked nitrile rubbers. The glass transition temperature of the cross-linked polymer both in cooling and heating has been determined.     

Superior antioxidant polymer films created through the incorporation of grape tannins in ethyl cellulose

Agro-wastes represent an abundant and economical source of antioxidant compounds. Extraction and incorporation of antioxidants from these compounds into ethyl cellulose films provides the basis for an active packaging material. Grape tannin extract (GT) incorporation into ethyl cellulose results in hydrogen bonding between polyphenols and ethyl cellulose strands, which allows for the polyphenols to remain active and to be securely incorporated. Incorporation of 0.5 % GT in ethyl cellulose produced a significant increase (p < 0.01) in antioxidant activity while not altering physical or mechanical properties. A higher loading of GT at 3.0 % into ethyl cellulose resulted in further improvement in antioxidant activity (12-fold), while a slight decrease in the tensile properties was noted due to the plasticizing effect of GT as a consequence of disruption of the intermolecular hydrogen bonding.     

Synergistic effect between POSS and fumed silica on thermal stabilities and mechanical properties of room temperature vulcanized (RTV) silicone rubbers

In this paper, both divinyl-hexa[(trimethoxysilyl)ethyl]-POSS (DVPS) and fumed silica were firstly introduced into polydimethylsiloxane (PDMS) system using as the cross-linker and the reinforcing filler respectively. And a series of novel RTV silicone rubbers synergistically enhanced by DVPS and fumed silica were prepared. The cross-linked networks in the novel RTV silicone rubbers have been studied by attenuated total reflection infrared spectroscopy, and the dispersions of POSS and fumed silica in these novel RTV silicone rubbers have been observed by means of scanning electron microscope (SEM). And thermal stabilities, thermo-oxidative stabilities and mechanical properties of these novel RTV silicone rubbers were studied by means of thermal gravimetric analysis and universal tensile testing machine, respectively. From the obtained results, it was found that synergistic effect between POSS-rich areas and fumed silica on thermal stability and mechanical property of RTV silicone rubber indeed existed. And the experimental results also exhibited that the thermal stabilities and mechanical properties of the novel RTV silicone rubbers were far better than those of the reference materials (DVPR and MTFR). The striking enhancements in thermal properties and improvements on mechanical properties of novel RTV silicone rubbers were likely attributed to the synergistic effect between POSS-rich domains and fumed silica. Meanwhile, it was found that the mechanical properties of RTV silicone rubbers prepared with a given amount of POSS cross-linker were enhanced with the increment of the loading amount of fumed silica.     

Preparation,characterisation and gas transport properties of trifluoroacetylated ethyl cellulose

A mixed ester of ethyl cellulose (EC) has been prepared by reaction of trifluoroacetic anhydride with the residual hydroxy groups of ethyl cellulose. The mixed ester is soluble in tetrahydrofuran, dichloromethane, chloroform, benzene and pyridine. FTIR and NMR spectra show that hydroxy groups of ethyl cellulose were replaced by trifluoroacetoxy groups. The trifluoroacetyl ethyl cellulose (TFAEC) has higher selectivity for oxygen relative to nitrogen, in gas transport, than unmodified EC. Annealing at an elevated temperature further improves selectivity for oxygen, whilst subsequent ageing at ambient temperature partially reduces oxygen selectivity. The tensile strength of TFAEC is virtually the same as that of unmodified EC, but the elongation to break is 200% higher than for EC.     

Influence of the functionalization pattern of ethyl cellulose on the interactions with polystyrene latex particles in aqueous mixtures

The interactions between polystyrene latex particles and ethyl cellulose (EC) with different functionalization pattern have been investigated. 3-Mono-O-EC and EC with statistical functionalization pattern in the anhydroglucose units were studied in aqueous solutions and dispersions. EC belongs to a group of polymers that phase separate upon heating. The two types of EC showed large differences in phase separation temperature, which was explained as an effect of different interactions with water due to different functionalization pattern. Both types of EC did adsorb on polystyrene particles, which indicated a favorable interaction between EC and polystyrene latex particles, however, in a different manner depending on the structure of EC. The conventionally synthesized ethyl cellulose with statistical functionalization pattern formed much stronger networks with polystyrene latex particles than 3-mono-O-EC did. The lower phase separation temperature and the slightly higher molecular weight of the conventional ethyl cellulose gave it higher preference for interacting with polystyrene latex particles to form network. Throughout the study, comparison is made with other cellulose derivatives like ethyl(hydroxyethyl) cellulose (EHEC) and carboxymethyl cellulose (CMC).     

Synthesis of inorganic-organic hybrids by incorporation of inorganic components into organic polymer using metal alkoxides

Inorganic-organic hybrids have been synthesized by incorporation of the inorganic component of Ti(OC₂H₅)₄ into the organic polymer of ethyl cellulose. The inorganic-organic hybrids did not dissolve in toluene used as a solvent for the starting materials. The ethanol was formed as a by-product of the alcoholysis condensation reaction between Ti(OC₂H₅)₄ and ethyl cellulose. These results suggest that ethoxy groups of Ti(OC₂H₅)₄ react with hydroxy groups of ethyl cellulose to form cross-linking bonds of –O–Ti–O–. The reaction of Ti(OC₂H₅)₄ with ethyl cellulose was further investigated by Fourier transform infrared (FT-IR) spectroscopy. The FT-IR spectroscopic experiments revealed that the Ti–O bond state of Ti(OC₂H₅)₄ was changed by refluxing a toluene solution of Ti(OC₂H₅)₄ with ethyl cellulose. The inorganic-organic hybrids have an interesting dielectric property; their dielectric constant is higher than that of ethyl cellulose and that of a simple mixture of TiO₂ and ethyl cellulose.     

Influence of cryogenic modification of silica on thermal properties and flammability of cross-linked nitrile rubber

The article presents the results of testing thermal properties and combustibility of butadieneacrylonitrile rubber with 18% contents of bounded acrylonitrile, NBR 18. Two types of silica, Zeosil 175C and Ultrasil VN-3, with different specific surfaces were used as filler. Zeosil 175C and Ultrasil VN-3 were modified via cryogenic dezaggregation method. The activity of unmodified and cryogenic modified silica toward butadiene-acrylonitrile rubber were investigated. The sulphur and peroxide vulcanizates contained 20, 30, 40, and 50 phr. of the filler were studied. The article discusses also the test results of thermal stability and flammability of NBR 18 containing silica prepared "in situ" from alkoxysilane precursor. The test results were obtained with the use of derivatograph, measurements of flammability by the method of oxygen index, and in air. The effect of the silica modification on the SEM and AFM was also examined. The method of cryogenic modification enables to achieve increase of mineral fillers activity towards elastomer and reduction in the flammability of NBR 18 vulcanizates. It has been found that the modification of the vulcanizates of NBR 18 with tetraethoxysilane that makes it possible to form silica "in situ" reduces the flammability of cross-linked rubbers.     

乙基氰乙基纤维素/甲基丙烯酸酯液晶溶液的研究

乙基氰乙基纤维素/甲基丙烯酸酯在一定的浓度下可以形成溶致性液晶,从液晶相的双折射纹理结沟和小角光散射的Hν散射花样可知这类液晶是胆甾型的。同时,在液晶相开始出现时及各向同性相完全消失时的临界浓度C_1和C_2均随着甲基丙烯酸酯的酯基链增长而降低。     

甲苯在纤维素乙基化过程中的作用

本文研究了甲苯在纤维素乙基化过程中的影响。实验表明,甲苯能明显提高乙基化反应速度和氯乙烷的反应效率;甲苯用量对乙基化反应程度和乙氧基的分布有显著的影响。在适量甲苯存在下所得到的乙基纤维素有较低的液晶转变温度、较宽的液晶温度范围和均匀的液晶态。     

Reactive blending of polypropylene and butadiene-acrylonitrile elastomer

Graft copolymer of polypropylene and butadiene-acrylonitrile random copolymer was prepared by reactive polymer blending in a melt without solvents. The process was performed by preliminary grafting of maleic anhydride groups to polypropylene and of isocyanate groups to butadiene-acrylonitrile copolymer, followed by blending of the modified polymers. The chemical reactions occurring in the process and the fraction composition of the copolymer were studied.     

The synthesis and thermotropic behaviour of an ethyl cellulose derivative containing azobenzene-based mesogenic moieties

An ethyl cellulose derivative containing azobenzene-based mesogenic moieties was prepared by the reaction of 4-methoxyazobenzene-4'-oxyacetic acid and ethyl cellulose by esterification in the presence of N,N' -dicylcohexylcarbodiimide and 4-dimethylaminopyridine. Its chemical structure and liquid crystalline properties were characterized by FTIR, 1 H NMR, POM, DSC and WAXD. The degree of substitution of the cellulose backbone by the azobenzene-based mesogenic moieties is 0.9. The polymer is thermotropic and exhibits liquid crystalline behaviour over the temperature range 125-172°C.     

Properties of solutions and films of blends of ethyl cellulose with polyvinylpyrrolidone and Poviargol

Viscosity properties of dilute and concentrated ethanol solutions of blends of ethyl cellulose with polyvinylpyrrolidone and Poviargol bactericidal formulation (silver metal nanoparticles stabilized with polyvinylpyrrolidone) were studied. The physicomechanical and thermomechanical properties of films prepared from solutions of the polymer blends were determined. Experiments on solvent vapor sorption showed that ethyl cellulose is incompatible with polyvinylpyrrolidone and Poviargol in the solid state in the entire composition range examined.