90 ЛЕТ КАФЕДРЕ ХИМИЧЕСКОЙ ТЕХНОЛОГИИ ПЛАСТМАСС СПбГТИ(ТУ)
The results of work of the Department of Chemical Technology of Plastics of the St. Petersburg State Institute of Technology (Technical University) on the study of polymerization and copolymerization of monomers in the presence of highly efficient initiating systems, on the development of processes of the directed synthesis and modification of polymers to create new polymeric materials for medical and biological purposes are summarized.
Water-soluble (co) polymers of N-vinylsuccinamic acid hydrazide are obtained as a result of polymer-analogous transformations in the interaction of hydrazine-hydrate of vinyl acetate copolymers with vinyl succinimide and polyvinyl succinimide. Using IR spectroscopy, potentiometric titration, elemental analysis, their structure and composition were established. The possibility of using copolymers as carriers of biofunctional substances of an acidic nature is shown.
The influence of a vinyl chloride – vinyl acetate copolymer on the compatibility of polyvinyl chloride and low density polyethylene in the production of rigid PVC films by the calender method is considered.
Modern methods for reducing the combustibility of novolac, epoxy and epoxy novolac oligomers used for the production of structural foams are considered. The results of studies on the application of chlorinated resins as fi re-resistant matrix, polyphosphates, intumescent carbon, and hallocyde nanotubes as fi re retardants are presented.
A technique has been developed for producing an unsaturated polyester resin by transesterifying the product of glycolysis of secondary polyethylene terephthalate using maleic and phthalic anhydride. The curing process was studied, it was found that the unsaturated polyester resin was cured by the action of oligoether acrylate (TGM-3), peroxide compound (methyl ethyl ketone peroxide) and accelerator (manganese hydroxide divalent, acetylacetone, cobalt stearate). The physic-mechanical characteristics of polymeric materials based on unsaturated polyester resin, the analysis of which indicates a high thermal stability, have been studied.
STRUCTURE AND PROPERTIES
The influence of the structure on the properties of the metal-polymer composite consisting of a polymer matrix in the form of epoxy resin (ED-20) with butadiene-styrene rubber (BSK), dispersedly filled with copper nanoparticles, is investigated. In the framework of fractal analysis, the real diameter of the aggregates of the initial filler particles was calculated for various concentrations and size of the filling particles and for different compositions of the polymer matrix. The concept of the structure of a polymer composite as a combination of two fractals (multifractals) was substantially used, which allows to determine the principles of the polymer matrix plasticity changes and to reveal the main factors affecting the degree of perturbation of its structure. Using fractal analysis methods, the influence of factors on the fractal dimension of the surface of initial filler particles aggregates and on the pattern of its dependence both on the degree of aggregation and on the fractal dimension of the frame of the particle aggregate is investigated The proposed approach enables prediction the fi nal parameters of aggregates of nanoparticles as a function of the size of the initial particles, their concentration and chemical properties of the surface of the polymer matrix.
Samples of polyester binder RO-4761 were irradiated using an ultraviolet device. The investigations established that the microhardness of the polymer along its cross section, from the surface to core of the sample, varies according to a parabolic law. With increasing time of UV exposure the sample, its microhardness increases. When the binder is fully cured, the parabolic curve transforms into a straight line. A new term is proposed that characterizes the change in microhardness in the volume of the cured polymer: “Volume anisotropy coefficient”.
The approaches to justification of ways to reduce the loss of plasticizers in the extraction of polyvinylchloride are considered. The parameters for evaluating the effectiveness of ways to reduce losses associated with the treatment of polyvinyl chloride with ultraviolet radiation are proposed The influence of the irradiation time on the mechanism of extraction of plasticizers with alcohols and the kinetics of extraction has been established.
SYNTHESIS AND TECHNOLOGY
The regularities of dispersion radical polymerization of n-butylacrylate in water-alcohol medium under the action of polymer tritiocarbonates based on copolymers of acrylic acid and N-isopropylacrylamide have been investigated. The conditions for the formation of a block copolymer with controlled molecular weight and high yield have been found. The conditions of formation of stable suspensions of block copolymers with unimodal particle size distribution have been determined.
RAW AND AUXILIARY MATERIALS
The properties of composites based on epoxy oligomer (EDO) and woody ash (WA) have been explored. As a result of the studies, it was proved that WA addition doubles the impact viscosity of composition, increases the density up to 40%, the hardness of the composite gradually increases with an increase of WA content. A uniform distribution of WA particles in the matrix is obtained.
Comprehensive studies of the structural, molecular and physico-chemical properties of cellulose nitrates from hemp fiber were carried out using modern research methods: capillary viscometry, IR Fourier spectroscopy, X-ray diffraction, gel permeation chromatography. The results of the study revealed features of the influence of inter- and intramolecular interactions in cellulose macromolecules from various types of fiber, the degree of crystallinity of the initial material, and the degree of polydispersity on the formation of qualitative characteristics of hemp cellulose nitrates.
ANALYSIS AND CALCULATION METHODS
For the first time, a method based on the registration of polarization and depolarization currents arising in wood in a non-uniform temperature field was used to study the properties of cellulose. The purpose of the method used is to record the relaxation of bound charges with a change in the temperature of the sample under study. It is shown that the detected low-temperature transitions have a crystal-crystal polarization mechanism, and the natural polymer cellulose is an active dielectric.
In the products obtained by thermoforming, the temperature stresses arising when fixing the shape of the product when the heated workpiece touches the forming tool are calculated. In addition, the residual stresses in the finished products are determined.
RECYCLING
The dilatometry method was used to study the effect of the concentration of domestic waste ash on the dependence of the specific volume of nanocomposites based on low density polyethylene on the temperature. The kinetics of crystallization in the first-order phase transition zone has been studied. The mechanism of crystallization depending on the filler concentration is established.
The article presents the results of a study of the rheological behavior of binary composites based on serial polyethylene grade LDPE 15803-020 with different content of microcellulose grade Filtracell, in a wide range of temperatures and shear rates during deformation through a capillary diameter of 1 mm and a length of 5 and 30 mm. Stable flow regime is manifested in the temperature range from 160 to 200°C for composites containing microcellulose in an amount of 30 wt.%, and its partial replacement with spent microcellulose (waste production of vegetable oils) can reduce the effective viscosity to 25%, but the upper limit of the temperature range is limited to the exudation of impurities (190°C). The Bagley correction is carried out, the coefficients of the equations describing the dependences of the true shear stress, regardless of the capillary length, are calculated.
APPLICATION
The main functions and requirements of packaging materials for foodstuffs are characterized. The classification of modern polymer packaging materials is discussed along with their properties and fields of their applications