The effect of changes in the stirring speed during suspension polymerization of vinyl chloride monomer (VCM) was investigated near the particle stabilization. Preliminary tests were conducted to check the highest conversion and information regarding the porosity and particle stabilization of two formulations, which are based on different concentrations of initiators and dispersing agents. The influence of stirring speed during the first 2 h of reaction was investigated for the best formulation, indicating that there was a proportional relationship between the increase in speed and the increase in conversion. The results presented suggest that the highest stirring speeds (900 and 1000 rpm) tended to achieve the same conversion with increasing reaction time. This was also observed with the lower stirring speeds (600 and 700 rpm); however, the conversions obtained were lower than those found with higher stirring speeds. The conversions achieved in 20 to 30 min of reaction were similar for all stirring speeds studied (20 min: 4.8% ± 1.3%; 30 min: 7.5% ±1.4%). However, there was greater variation in conversion for longer reaction times (60 min: 15.9 ± 2.8%; 120 min 36.5 ± 2.4%). Stability of the particles was achieved for 6-8% conversion for all stirring speeds used when breakage and coalescence processes stop. The conversion interval obtained in this work was smaller than the values found in the literature (between 15 and 20%). The effect of stirred conditions on particle size distribution showed that better stability of the particle size occurred at 900 rpm for the system studied. In this case, variations in the particle size decreased when the conversion increased.

The main raw material used in the production of polyvinyl chloride (PVC) is vinyl chloride monomer (VCM).Controlling the purity of VCM is essential to control the parameters of the polymerization reaction and the properties of PVC resins, such as the molecular weight, porosity, particle size and thermal stability, since some organic contaminants react as co-monomers and are undesirable. Two methods of concentration by adsorption and thermal desorption were developed using the adsorbents Tenax-TA and Tenax-TA/ Carboxen 1000/Carbosieve SIII, applying full and fractional factorial design to optimize the variables.Organic contaminants were identified in the various stages of production, storage and recovery at four distinct points in the process, leading to the identification of nineteen substances in all the samples, including aliphatic and aromatic hydrocarbons, organochlorines, alcohols, phenols and phenones. The contaminants that showed the highest relative abundances were styrene, benzene, toluene, naphthalene, 1,2-dichloroethane, 1-octanol and 1,3-butadiene. Among these contaminants, 1,3-butadiene and styrene have been reported in the literature as potent inhibitors of VCM polymerization. Using PCA multivariate analysis, it was possible to confirm that there are statistically significant differences in the characteristics of the VCM. Samples from four different points in the process were successfully classified into three different groups, in each of which the main contaminants responsible for the differentiation of the samples were identified. This work is innovative in the application of a TD-GC-MS-based system, for the identification of organic contaminants in VCM produced industrially, and in the investigation of its process by multivariate analysis.