The polymerization of VINYL acetate in methanol, ethyl acetate and acetic acid is studied and the conversion-times are reported. Due to the importance of molecular weights of polymers from the SOLUTION and bulk methods, and their uses in optimization of polymerization, specially in controlling the properties of the polymer, the viscosity, molecular weight and molecular weight distributions are measured and reported. STATISTICAL calculations and CURVE fittings of the data on the molecular weights and the solvent (methanol-monomer ratio) indicate a very low mathematical residues. The conversions are compared with bulk, and the effect of temperature on SOLUTION polymerization in ethyl acetate is used to show the importance of high ACTIVATION energy of the initiator (benzoyl peroxide). TRIETHYL AMINE, being used as catalyst in SOLUTION polymerization of VINYL acetate (ethyl acetate and acetic acid), indicate a faster conversion.

PVC in the form of emulsion resin is used in plastisol technology. Among its disadvantages: resin degradation during melt processing, high melt and gel temperature, resin's high viscosity in gel and melt temperature and low solubility can be mentioned. Copolymerization of VINYL chloride wih other monomers is a suitable route to modify such properties. VINYL acetate comonomer improves many of the PVC problems. In this study copolymerization of VINYL chloride with 15.2 percent VINYL acetate was performed in a batch emulsion copolymerization system. VINYL chloride content in both gas and liquid phase in the reactor, pressure variation and the effect of initiation on the reaction kinetics were investigated. Chemical structure and copolymer composition were characterized by FTIR and NMR spectroscopy. K-Value of the copolymers which is related to molecular weight was determined by SOLUTION viscometry.

As we know oxygen is one of the main inhibitors of polymerization of VINYL acetate. Therefore, nitrogen is used in order to make sure of system's high purity. To maintain purity it is necessary to find out the rate of the oxy-gen SOLUTION in polymerization system under different conditions of polymerization. It is concluded that incoming nitrogen to the system would remove the oxygen from the system and on the other hand the increase in temperatures a great help. The time length for this process is evaluated in polymerization system at the same time.

Poly (VINYL acetate) is synthesized via SOLUTION polymerization, and then it is converted to poly(VINYL alcohol) by alkaline alcoholysis. The aim of the work study was to investigate STATISTICALly the influence of reaction variables in VINYL acetate polymerization, the conversion of this monomer to polymer, degree of branching of acetyl group in poly(VINYL acetate), as well as the molecular weight of poly(VINYL alcohol), using Taguchi experimental design approach. The reaction variables were polymerization time, molar ratio of initiator to monomer, and volume ratio of monomer to solvent. The STATISTICAL analysis of variance of the results revealed that all factors have significantly influenced the conversion and degree of branching. Volume ratio of monomer to solvent is the only factor affecting the molecular weight of poly(VINYL alcohol), and has the greatest influence on all responses. By increasing this ratio, the conversion, degree of branching of acetyl group in poly(VINYL acetate), and molecular weight of poly(VINYL alcohol) were increased.

Telomerization of VINYL acetate (VAc) in chloroform and with 2,2’-azo isobutyronitrile (AIBN) initiator, was carried out to synthesize poly (VINYL acetate) (PVAc) with tri-chloromethyl (CCl3) end group which is called VAc telomer. The molecular structure and molecular weight distribution (MWD) of VAc telomers were characterized by 1H NMR spectroscopy and gel permeation chromatography (GPC). The effect of chloroform and AIBN on number average degree of polymerization (Dpn ) and percent of telomerization were investigated. The kinetics of telomerization was studied and chain transfer constant of chloroform was determined. The synthesized PVAc with CCl3 end group (VAc telomer) was used as macroinitiator in atom transfer radical polymerization (ATRP) of methyl acrylate (MA) with CuCl/2,2’- bipyridine catalyst system to synthesize novel block copolymers of VAc and MA. Molecular structure and MWD of the PVAc–b–PMA copolymers were characterized by 1H NMR spectroscopy and GPC.

The copolymers (CPVAc) with various proportions of N-p-chloromalemide (CMI) and VINYL acetate were prepared by free radical polymerization in tetrahydrofuran (THF) using 2.2'-azo-bis-isobutyronitrile (AIBN) as an initiator at 70±2 C. The series of copolymers (CPAVc1 - CPAVc9) were characterized by FTIR and 1H NMR spectroscopic methods. Solubility and viscosity parameters were studied for all the nine copolymers. The viscosity data were used to evaluated Huggins (KH), Kraemer (KK), Schulz-Blaschke (KSB), and Martin (KM) constants. Their energy of ACTIVATION was calculated from thermo gravimetric analyses of the copolymers using Broido's method and copolymer compositions were established by elemental analysis. The copolymer chains were comprised of the first monomer M1 (CMI) and the second monomer M2 (VAc). Units were distributed in a particular sequence for a definite chain length which was dependent on the feed composition of each monomer. The reactivity ratios of copolymerization were computed by using Finnmen-Ross and Kelen-Tudos methods and were found to be r1=1.177 and r2=0.419.

In this article, an attempt has been made to estimate the amount of sound transmission loss in a flat oval channel by applying the approach of STATISTICAL energy analysis. Correct estimation of sound transmission loss in an air conditioning channel is of great importance due to the harmful effects of noise pollution in the environment on human health. Simulation with the STATISTICAL energy analysis method is a powerful approach to estimate sound and vibration in problems in which we deal with complex and multi-part systems; is considered. In this method, first, a system is divided into several subsystems, and then by writing a matrix equation that includes the energy exchanges between subsystems and energy loss coefficients; It is investigated from the perspective of vibration and sound estimation.On average, the model presented in this research is able to estimate the sound transmission loss in different dimensions of the air conditioning channels according to the experimental results in the accuracy range of ± 2.5 dB. Considering that it seems that the results obtained from modeling with this method are in good agreement with the experimental data; The results of this research can be used as an efficient approach to estimate noise in oval shaped channels stretched in different lengths.

Poly(VINYL alcohol) (PVA) is a water soluble polymer with excellent physical and chemical properties. The basic properties of this polymer depend on its molecular weight, degree of hydrolysis and distribution. Since the commercial applications of PVA are many and varied, therefore, a special grade of PVA with considerable properties is required as an emulsifier. A polymerized ester can be used for preparation of PVA types, because VINYLalcohol monomer does not exist in the free state. The characteristics of the preparation of poly(VINYL acetate) (PVAc) are very important in the manufacture of PVA. In this work, a partially hydrolyzed grade of PVA having characteristics suitable for application in emulsion polymerization of VINYL acetate (VAc) (Mv: 77200, hydrolysis degree: 89.2%) was prepared by investigation of reaction conditions for SOLUTION polymerization of VAc by the aids of α,α' azobisisobutyronitrile (AIBN) initiator in methanol and the subsequent saponification reaction of the resulted PVAc in the presence of NaOH. This was including investigation of the effect of [VAc]/[AIBN] ratio and polymerization time for preparation of PVAc at 60°C in terms of VAc conversion and PVAc molecular weight, then the effect of saponification time of PVAc in terms of the molecular weight and hydrolysis degree of PVA product. In case of some samples, concentration of the monomer relative to that of the initiator plays an important role in VAc conversion value and controlling the PVAc molecular weight. The results from saponification of PVAc samples revealed that, only one of the samples was that its saponification resulted in PVA material desired molecular weight at 1 h. 1H NMR Spectra of PVAc and PVA were used to show a branched molecular structure of PVAc and estimation of the degree of hydrolysis of a PVA sample. The presence of typical characteristics absorption bands in IR spectra of PVAc and PVA samples agrees with proposed structures. To confirm the result earned, the characteristics of PVA obtained were compared with those of the commercially used PVA grades (Mowiols).