Perspective thermally stable thermoset binders for polymer composite materials

Brief review of the modern state in the field of thermally stable thermoset resins used as binders for engineering polymer composites in presented. Synthesis, processing, properties, and application of such materials are discussed. The list of binders includes polyimide PMR resins, oligoimides with reactive end groups, bismaleimides, and phthalonitrile resins.     

Improvement of quality of carbon fiber rods by the impregnation of carbon fibers with oligoorganosiloxanes

Russian Chemical Bulletin - The effect of the impregnation of the UKN-M-6K carbon fiber with organosilicon binders on the characteristics of carbon fiber rods was studied. Solutions of...     

Preparation and properties of wooden fiberboards with phenol cardanol formaldehyde adhesives

The results of a study of wooden fiberboards, for which phenol cardanol formaldehyde resins with different cardanol content were used as binders, are shown. The influence of technological factors on the bending strength of fiberboards and their water absorption in the case of the use of such binders is shown.     

A study of mica structure and strength properties of polymer materials based on it

The mica microstructure is studied, and its shape and particle sizes are found as dependent on coating technology. Using epoxy and organosilicon polymers, several lots of materials with different contents of mica are prepared and mechanical tests are performed. The optimal amounts of mica wherein the initial strength characteristics are preserved are found. The thicknesses of epoxy and organosilicon polymer wherein high optical decorative properties of mica are preserved are determined.     

聚合物粘结磁体用Nd—Fe—B微晶磁粉的氧化行为及防护

采用有机硅树脂、硅烷偶联剂和重铬酸盐处理快淬Ｎｄ－Ｆｅ－Ｂ微晶粉表面，通过热氧化增重试验２、湿热环境试验以及差示热分析法（ＤＴＡ）研究了上分的氧化行为和抗化效果，实验表明，上述方法能提高磁粉的抗氧化行为。     

Control of the plasticity of organosilicon rubbers by their modification with polypyrrole

Modification of organosilicon rubbers SKTN and SKTV with polypyrrole was studied. The modifying agent was synthesized directly in the rubbers containing iron trichloride acting as oxidant and catalyst, using the diffusion procedure and impregnation of organosilicon rubbers with pyrrole-2-carboxylic acid in supercritical carbon dioxide. Changes in the ductility and viscosity of the composite materials were analyzed.     

Thermal study of phenol–formaldehyde resin modified with cashew nut shell liquid

In this study, an experimental phenol–formaldehyde resin with 20% phenol replacement by cashew nut shell liquid (CNSL) was studied and compared with a conventional phenol–formaldehyde resin synthesized totally from petrochemical raw materials. The resins were characterized with standard lab analysis for their physicochemical specifications, while their thermal properties were studied with thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). For comparison reasons pure CNSL and wood were also included in the TGA study. A DSC study conducted both for the neat resins and the system wood–resin as to examine the effect of wood on the curing performance of the resins in the real time conditions of their usage at the wood-based panels industry.The adhesion strength of these resins was investigated by their application in plywood production. The plywood panels were tested for their shear strength and wood failure performance while their free formaldehyde emissions were determined with the desiccator method. It was proved that although the neat CNSL modified PF resin (PCF) cures at longer time and higher temperature than a conventional PF resin, wood affects it more significantly, resulting in the evening of their curing performance. This is a novel finding that manifests the possibility of replacing a convention PF resin by a CNSL modified one in the plywood production, without changing any of their production conditions and with improvement to their overall properties.     

Modification of construction carbon-reinforced plastics with carbon nanoparticles

The influence of fullerenes and their derivatives on the formation of carbon-reinforced epoxy composites and service characteristics of the construction carbon-reinforced plastics thus formed have been studied. The technology of homogeneous distribution of two- or four-walled carbon nanotubes in the bulk of epoxy oligomers has been developed. A lightning-protective coating on the basis of a carbon-reinforced plastic (CRP) with a carbon-nanotube modifier has been designed. Owing to increased electrical and heat conduction, high thermal destruction temperature, and improved performance characteristics, the designed CRP coating exhibits improved safe damageability under direct stroke and lower weight compared to conventional brass grid lightning-protective coatings.     

Preparation and Structure of Polyimides Derived from H Complexes of Benzophenonetetracarboxylic Acid with Diaminodiphenyl Ether

The possibility of using H complexes of dialkyl dihydrogen 3,3',4,4'-benzophenonetetracarboxylates and 4,4'-diaminodiphenyl ether and of polyimides prepared therefrom as polyimide foam materials, carbon-reinforced plastics, and foam composites was examined.     

Research and synthesis of organosilicon nonthrombogenic materials containing sulfobetaine group

A novel organosilicon sulfobetaine was synthesized through the reaction of organosilicon containing tertiary amino with 1,3-propanesulfone. Then this organosilicon sulfobetaine was coated onto polyurethane and organosilicon surface to improve their blood compatibility. The existence of sulfobetaine structure on the surface of materials was revealed by ATR-FTIR and XPS. The thermo-capability of synthesized silicone rubber, containing sulfobetaine was revealed by TGA. The blood compatibilities of organosilicon sulfobetaine and other materials such as silicone and PU as reference coated with them were evaluated by platelet-rich plasma adhesion experiment. The novel segmented silicone rubber containing sulfobetaine structure showed perfect blood compatibility.     

The biodeterioration of synthetic resins used in conservation

Synthetic resins have been extensively employed by artists in their works of art, e.g. as paint binders, or by conservators for conservation treatments, e.g. as stone consolidants and protectives. It is generally thought that synthetic resins are less prone to chemical, physical and biological deterioration than other organic products but there are many articles in the scientific literature and some reports in the conservation of cultural heritage literature claiming that microorganisms are capable of degrading synthetic resins. This paper reviews the researches on the biodeterioration of synthetic resins used in the conservation of cultural heritage, including stone, painting and textile materials, carried out in the last fifty years.     

Classification and identification of organic binding media in artworks by means of Fourier transform infrared spectroscopy and principal component analysis

Fourier transform infrared spectroscopy is a powerful analytical technique to study organic materials. However, in Cultural Heritage, since the sample under analysis is always a complicated matrix of several materials, data analysis performed through peak-by-peak comparisons of sample spectra with those of standard compounds is a tedious method that does not always provide good results. To overcome this problem, a chemometric model based on principal component analysis was developed to classify and identify organic binding media in artworks. The model allows the differentiation of five families of binders: drying oils, waxes, proteins, gums, and resins, taking into account the absorption bands in two characteristic spectral windows: C–H stretching and carbonyl band. This new methodology was applied in the characterization of binders in three kinds of artworks: papers of historical, archeological, and artistic value, easel paintings, and polychromed stone-based sculptures.     

Effect of glass transition temperature of polymeric binders on properties ceramic materials

In the paper are presented the studies of the effect of glass transition temperature of new water-thinnable polymeric binders on the properties of ceramic materials obtained by die pressing. The parameters of ceramic samples comprising polymeric binders have been compared with those of samples comprising poly(vinyl alcohol) (PVA) — water-soluble binder. When using poly(acrylic-styrene) (AS), poly(acrylic-allyl) (AA) and poly(vinyl-allyl) (VA) water-thinnable binders, materials of greater density and mechanical strength were obtained in the green state as well as after sintering than those in the case of using PVA. The dependence of the chemical structure of the binders applied on the properties of samples such as the glass transition temperature and hydrophobic-hydrophilic balance of the copolymers has been discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Production of Composite Materials from Peat and Wood by Explosive Autohydrolysis

Technology for obtaining peat and peat-wood composite materials by the explosive autohydrolysis method without using synthetic binders was developed. The optimal conditions of an explosive autohydrolysis of peat and peat in the presence of wood were found: pressure 1.62 MPa, temperature 210°C, treatment duration of 10 min in an explosive autohydrolysis reactor. Peat and peat-wood composite materials were obtained. In their strength characteristics (bending strength up to 14.68 MPa) and heat conductivity these materials compare well with the conventional heat-insulating materials and can be used as construction materials.

     

Alkyd paints in art: Characterization using integrated mass spectrometry

Alkyd resins have been commonly used as binders in artist paints since the 1940s. The characterization of alkyds in samples from artworks can help to solve attribution and dating issues, investigate decay processes, and contribute to the planning of conservation strategies. Being able to assess the components of industrially formulated paint materials and to differentiate between different trademarks and producers is extremely interesting and requires multi-analytical approaches.     

Synthesis,cure, and composite properties of mixed allyl/propargyl cyclopentadiene resins

A series of thermosetting resins were synthesized via phase transfer reaction of allyl chloride and propargyl bromide with cyclopentadiene in the presence of a strong base. Feed ratios of 1 : 1, 3 : 1, and 5 : 1 allyl chloride to propargyl bromide were used to give resins with varying amounts of propargyl and allyl functionality. In all cases the resins could be thermally cured, without added catalyst, at temperatures below 275°C to give black, glassy, brittle materials with densities of 1.15. TGA evaluation of the resins, with heating to 1000°C, resulted in carbon yields ranging from 48 to 66% with increasing propargyl functionality causing increased values. Physical mixtures of ACP and PCP resins were also made and evaluated. Cure of the mixed materials also occurred below 275°C, and carbon yields were comparable to the corresponding APCP resin. APCP/carbon fiber composites gave good mechanical properties with flexural modulus values of 115–130 GPa and flexural strength values of 1000 MPa. Carbonization of 1 : 1 APCP/carbon fiber composites provided materials with interlaminar strength values of approximately 1.14 MPa. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 2869–2876, 1998     

Chemical composition and porous structure of polymer-derived silicoboron carbonitride ceramics prepared via a monomer route

Polymer-derived silicoboron carbonitride (SiBCN) ceramics were facilely prepared using organosilicon monomers tris(dichloromethylsilylethyl)borane and bis(trimethylsilyl)carbodiimide as the starting materials. The polymer precursors were obtained either without adding styrene or by adding an appropriate amount of styrene into the mixture of the organosilicon monomers, followed by heat treatment and purifying. The chemical composition and pore structure of the polymer-derived SiBCN ceramics were studied. It was found that styrene diluted the monomers and hindered their chemical reaction from forming the polymeric network. The polymer precursor prepared with styrene was composed of boron-modified polysilylcarbodiimide as the matrix and dispersed polystyrene mainly of sizes 20–50 μm. Accordingly, a polymer-derived SiBCN ceramic with a three-dimensional continuous macroporous structure containing pores mainly of 20.9–58.1 μm with a total porosity of 74% was achieved. The B/N atomic ratio reached 0.58 with low oxygen content of 2.81 wt%, which satisfied the requirement for high-temperature application.     

Making polymer concrete and polymer mortar using synthesized unsaturated polyester resins from poly(ethylene terephthalate) waste

Depolymerization of poly(ethylene terephthalate), PET, waste was studied in the presence of manganese acetate catalyst and propylene glycol (PG) at different weight ratios. The glycolyzed products were analyzed for hydroxyl value and the amount of free glycol. A series of unsaturated polyesters based on the glycolyzed products, maleic anhydride and styrene, were prepared. Molecular weights and curing behavior of these polyesters were determined. Polymer concrete (PC) and polymer mortars (PM) made with these resins were investigated for their compressive strength. It has been found that the properties of PC and PM obtained from resins based on recycled PET are comparable to PC and PM made from virgin materials.     

Thermal deformation properties of oligoepoxide-based binders

Crosslink density and a number of other physicochemical parameters of composites are investigated as functions of the initial mixture composition by the example of materials comprising bisphenol A-based epoxy oligomers with different molecular masses, nitrogen-chlorine-containing oligoepoxide, epoxy novolac block copolymer, epoxyurethane modifier, and amine and anhydride curing agents. It is shown that the incorporation of elasticizers into densely crosslinked polymers reduces the free kinetic volume of the latter. The modification of binder makes it possible to obtain composites that are both well deformed and capable of recovering initial shape at T ≥ T _g. The properties of glass-and carbon-reinforced plastics prepared using the developed elasticized binders by the contact molding are described. This method ensures defect-free bending deformation that exceeds that achieved in the case of compression molding. A rubber-like deformation technology is elaborated that enables one to employ blow molding for the production of open-contour items from cured blanks and closed-contour items that cannot be produced by winding because of their configuration.     

Binding in Paper-Like Composites Based on Mineral Fibers

The structural and physical parameters of paper-like composites based on mineral fibers with aluminum polyhydroxo complexes as binders were determined and analyzed. Samples of the composites based on mineral fibers differing in the content of binders were analyzed by IR spectroscopy and electron microscopy. Formation of interfiber bonds in the materials studied was hypothesized.