Кинетика окисления полиизопрена в присутствии активных добавок

Analysis of changes in the structure and properties of polyisoprene films was carried out. The samples contained chemically active additives (antioxidants, antiscorchings) and were subsequenly warmed up.Проведен анализ изменения структуры и свойств пленок полиизопрена, содержащих химически активные добавки (противостарители, антискорчинги) с последующим прогревом образцов

Atmospheric forcing validation for modeling the central Arctic

Author Posting. © American Geophysical Union, 2007. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 34 (2007): L20706, doi:10.1029/2007GL031378.We compare daily data from the National Center for Atmospheric Research and National Centers for Environmental Prediction “Reanalysis 1” project with observational data obtained from the North Pole drifting stations in order to validate the atmospheric forcing data used in coupled ice-ocean models. This analysis is conducted to assess the role of errors associated with model forcing before performing model verifications against observed ocean variables. Our analysis shows an excellent agreement between observed and reanalysis sea level pressures and a relatively good correlation between observed and reanalysis surface winds. The observed temperature is in good agreement with reanalysis data only in winter. Specific air humidity and cloudiness are not reproduced well by reanalysis and are not recommended for model forcing. An example sensitivity study demonstrates that the equilibrium ice thickness obtained using NP forcing is two times thicker than using reanalysis forcing.This research is supported by the National Science Foundation Office of Polar Programs (under Cooperative Agreements Nos. OPP-0002239 and OPP-0327664) with the International Arctic Research Center, University of Alaska Fairbanks, NSF grant OPP- 0424864 and by Russian Foundation for Basic Research, No. 07-05-13576

A model for producing polymer stabilizers of composites with a given macromolecule composition

An attempt has been made to obtain a working technological formula that regulates the addition of comonomer over time, which ensures the synthesis of a copolymer macromolecule with a constant composition and, accordingly, with predicted properties of both the copolymer and its modified porous composite materials. Mathematical modeling is based on the theory of the kinetics of copolymerization, which takes into account the reactivity of monomers by means of copolymerization constants of reacting comonomers. The starting base was the kinetics of the copolymerization of two comonomers, significantly differing in their reactivity, which required a sequential, stepwise supply of a less reactive monomer to the reaction medium with a more active monomer. This technological technique contributes to maintaining the constancy of the initial ratio of comonomers and, accordingly, the synthesis of a copolymer with a constant composition, structure and properties. The dependence of the sequence of supply of comonomer to the reaction medium required the introduction of a generalized effective binary copolymerization rate coefficient. To find the generalized coefficient of the copolymerization rate, the operation of logarithm was performed and the current expression of the dependence of the concentration change of the more active monomer in time in a linear form was translated. This mathematical technique made it possible to use software to process reference information to obtain the necessary coefficients for the working formula. As a result of mathematical modeling using the basic principles of binary copolymerization, the law of effective masses, and the least squares method, a working formula is obtained that allows one to regulate the given introduction of a less active monomer into the reaction medium in time. The model is analyzed using background information, the basic concepts of binary copolymerization and can be used in technological calculations when producing copolymers with specified characteristics in composition and structure

Application the criteria in the description of thermal oxidation degradation polydienes

The relationship of molecular structural characteristics of polydienes and their macroscopic properties in thermal oxidation processes was examined

Kinetics of polyisoprene oxidation in the presence of active chemical additives

Analysis of changes in the structure and properties of polyisoprene films was carried out. The samples contained chemically active additives (antioxidants, antiscorchings) and were subsequenly warmed up

The effect of paint material composition on the properties of coatings

The influence of the dose and the nature of the fillers and plasticizers on technological and technical properties of coatings based on acrylic polymers was considered. Improvement in the properties of acrylic paints when used as a plasticizer dibutylphthalate was found

Simulation of polidiene oxidation kinetics

Synthetic isoprene rubber (SIR) is similar in structure and to the properties of natural rubber (NR). Currently, it can almost completely replace NR in the production of automobile tires and rubber products. An urgent task is to study the aging processes of polymers and their products, assess the impact of various factors on the oxidative stability of polymers and the selection of effective ways to protect polymers from aging. We simulated aging of inhibited (commodity) and reprecipitation (purified) polyisoprene

RECEPTION AND OXIDISING AGEING OF FILMS OF RUBBERS

Oxidising ageing полидиенов, especially important for an estimation of operational durability of protective films is considered

THERMOOXIDATION OF POLYDIENES ELASTOMERS

Chemical reactions in polymers are considering as thermo-fluctuation process. Studying of influence of defects of structure macromolecul on molecular weight and molekuljarno-mass distribution polydienes at thermooxidation elastomers

MEHANOHIMICHESKY TRANSFORMATIONS OF POLYMERS AT REPEATED CHANGES OF TEMPERATURE, PRESSURE AND SHIFT

The changes of molecular-structural and rheological characteristics of carbon polymers in the multiple repetition of cycles «heating + pressure - shear - pressure reduction + cooling»