Abstract Poly(vinyl chloride) (PVC) resins constitute the third most important plastic materials available commercially, in terms of worldwide volume production, and can be manufactured through several polymerization mechanisms, including free radical, ionic and redox polymerization processes. Approximately 80% of the worldwide commercial PVC production is performed through suspension polymerization processes in batch mode, due to intrinsic problems of continuous suspension polymerization processes, such as polymer incrustation in reaction vessels, transport equipment and pipes. For this reason, the present review provides an extensive bibliometric survey, including papers and patents, on attempts to develop continuous polymerization process technologies for PVC manufacture. Particularly, the present survey characterizes the degree of maturity and the main bottlenecks of continuous PVC processes that have been frequently overlooked in the technical literature.

Abstract Previous studies have investigated the preparation of heterogeneous biocatalysts based on the immobilization of lipases on distinct types of supports. However, few works have investigated the influence of the textural properties of these supports on the immobilization parameters. Thus, the present article reports the preparation of copolymers based on divinylbenzene by aqueous suspension polymerizations, using different amounts of porogenic agents to prepare particles with distinct textural properties. The particles were used for immobilization of lipase from Candida antarctica fraction B and the performance of the biocatalysts was evaluated in hydrolysis reactions, using p-nitrophenyl laurate as substrate. The use of Sty/DVB particles resulted in higher immobilization yields (89.5% and 99.2%) and higher hydrolytic activities, when compared to the Sty/VBC/DVB particles. Particularly, the increase of the pore diameters of the particles resulted in higher immobilization yields. Also, the hydrolytic activities depended simultaneously on the average pore diameter, porosity, and specific area (the most influential variable) of the supports. Thus, it was observed that the distinct morphological features of the polymer support can exert significant and conflicting effects on the final biocatalyst performance, since the specific surface area is normally expected to decrease with the increase of the average pore size.

Abstract The present work reports the implementation of the Hazard Analysis Critical Control Point (HACCP) methodology to analyze the water purification system of a pharmaceutical site, in order to assure the system quality and prevent failures. As a matter of fact, the use of HACCP for development and implementation of Quality Risk Management (QRM) is not usual in pharmaceutical plants and it is applied here to improve the performance of the water purification system of a polymerization pilot plant used to manufacture pharmaceutical grade polymer microparticles. Critical Control Points (CCP) were determined with the aid of a decision tree and questions were made to characterize whether identified hazards constitute actual CCPs and should be monitored. When deviations were detected, corrective actions were performed and action plans were used for following-up and implementation of corrective actions. Finally, microbiological and physicochemical parameters were analyzed and the obtained results were regarded as appropriate. Therefore, it is shown that HACCP constitutes an effective tool for identification of hazards, establishment of corrective actions and monitoring of the critical control points that impact the process and the quality of the final pharmaceutical product most significantly.

Abstract Polymer nanoparticles have been widely used in many biomedical applications, constituting a major incentive for immobilization of proteins. Poly(methyl methacrylate) nanoparticles were synthesized through miniemulsion polymerizations and used as supports for bovine serum albumin immobilization. Particularly, the effects of surfactant type (anionic sodium dodecyl sulfate and cationic cetyl trimethyl ammonium bromide) surfactant concentration and monomer holdup on some of the final nanoparticle properties (particle sizes, zeta potential and protein load) were characterized with help of statistical experimental designs for the first time. Results showed that the characteristics of the surfactant controlled the BSA adsorption efficiency, with enhanced rates of adsorption on the anionic particle surfaces, showing that the surfactant exerts fundamental effect on functionalization of emulsified polymer particles, which must be explicitly acknowledged in studies of polymer particle functionalization with proteins. Finally, BSA adsorption was shown to follow a multilayer process, given the better fitting with the Freundlich model.

Abstract The main objective of the present work is to produce and characterize urea granules coated with polymers prepared with aqueous solutions of acrylic acid and glycerol. Both coating and drying of urea granules were performed in a fluidized bed reactor. Fourier transform infrared spectroscopy analyses indicated the presence of poly(acrylic acid) and acrylic acid / glycerol copolymers on the granule coating and the formation of chemical bonds between urea and the polymer coating. Scanning electron microscopy images showed that the original and coated urea granules presented different characteristics, reinforcing the idea that coating occurs in the fluidized bed. Finally, rates of urea release showed that the coated granules presented slightly slower rates of urea dissolution in water due to the presence of the coating layer. Therefore, it is shown that it is possible to produce coated urea granules through in-situ polymerization onto the granule surface using a fluidized bed.

Abstract Gelatin is employed in pharmaceutical applications because of its biodegradability, biocompatibility and low toxicity. However, it may be necessary to promote gelatin crosslinking in order to develop drug release systems and extend release times. SEC analyses are used here for the first time to monitor the evolution of molar mass distributions of gelatins during treatment with glycerol and glucose in dispersed media. Unambiguous experimental evidence of gelatin crosslinking in presence of sugars and glycerol has yet to be presented. SEC results indicate that average molar masses decrease during gelatin treatment, while FT-IR analyses indicate that gelatins are subject to structural modifications during processing, which can explain the decrease of gelatin solubility after treatment. The results presented here indicate the importance of using SEC techniques to monitor gelatin crosslinking, as they seemingly contradict previously published results that make use of indirect measures for this purpose.

Abstract Poly(vinyl acetate) (PVAc) particles find many uses in the biomedical field, including the use as particle embolizers. Particularly, embolizing particles can combine physical and chemical effects when they are doped with pharmaceuticals. For this reason, the adsorption of bovine serum albuminum (BSA) and lysozyme (used as model biomolecules) on PVAc particles produced through suspension polymerization is studied in the present manuscript in a broad range of pH values. It is shown that significant amounts of BSA and lysozyme can be adsorbed onto PVAc particles in the vicinities of the isoelectric point of the biomolecules (0.65mg of BSA and 1.0mg of lysozyme per g of PVAc), allowing for production of chemoembolizers through adsorption. Particularly, it is shown that lysozyme still presents residual activity after the adsorption process, which can constitute very important characteristic for real biomedical applications.

Abstract Oxaliplatin was inserted into polymeric matrices aiming to study the interaction of this drug with these polymers and its capability to diffuse to the environment. Tested polymers were: (1) polyethylene glycol (PEG), (2) poly(lactic-co-glycolic acid) (PLGA), and (3) a copolymer of them (PLGA-PEG). The latter two were synthesized by us using polycondensation in bulk. Oxaliplatin was included in the matrices by the melt mixing process followed by casting. Fourier tran sform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR) and X-ray diffraction (DRX) studies of the polymers were performed proving the obtaining of the desired materials. In addition, the interaction between drug and matrices and the release profile of the oxaliplatin from these matrices were analyzed. Among them, PEG did not control the oxaliplatin release. In turn, PLGA and PLGA-PEG present drug release profiles quite similar. Oxaliplatin was completely released from PLGA and PLGA-PEG in 5 hours, by a relaxation mechanism. There was no evidence of oxaliplatin interaction with the different polymers. In addition, as the PEG improves the biocompatibility and biomasking, obtained results prove the obtaining of a drug release system, which allowed the total use of the drug improving the cancer treatment and even the welfare of the patients.

Nanocompósitos de poli(succinato de butileno) (PBS) e argila montmorilonita organofílica foram sintetizados via polimerização in situ, em três diferentes concentrações (4, 6 e 8% em massa). Os produtos obtidos foram caracterizados por diversas técnicas. Entre elas, a difração de raios X foi útil para comprovar o aumento do espaçamento interlamelar da argila devido à incorporação das cadeias de polímero. As técnicas de análise térmica mostraram que o método de polimerização in situ gerou materiais com menores estabilidades térmicas, comparadas ao polímero puro, devido à dificuldade de crescimento das cadeias de polímero na presença da argila. A técnica de RMN de baixo campo permitiu identificar que a estrutura esfoliada predomina nos nanocompósitos.

Nanocomposites based on poly(butylene succinate) (PBS) and organophilic montmorillonite were synthesized via in situ polymerization using three different clay compositions (4, 6 and 8 wt%). The products were characterized by several different techniques. X-ray diffraction was useful to confirm the increase of the interlayer spacing of the clay due to the presence of the polymer chains among layers. Thermal analysis indicated that the polymerization method chosen led to materials with lower thermal stability compared to the pure PBS, due to the difficulty of chain growth in the presence of the clay. Low-field NMR technique was used to assess clay dispersion in the polymer, with exfoliated structures predominating in the nanocomposites.

Tamoxifen (TXF) is currently the only hormonal agent used for treatment of breast cancer. Although very effective, TXF presents low solubility in water, which affects its absorption and bioavailability. A common strategy to overcome this barrier is the formulation of a drug delivery system (DDS) in order to increase the drug stability and improve the treatment effectiveness. Reversible addition-fragmentation chain transfer (RAFT) polymerization is the most versatile method of controlled/living radical polymerization (CLRP), allowing for synthesis of well-defined polymers and being adapted to a wide range of polymerization systems. Miniemulsion polymerization is a dispersed system that is commonly used to prepare nanoparticles (NP) with 50 to 500 nm of diameter. The aim of this work was to evaluate the effect of the in situ incorporation of TXF during miniemulsion conventional and RAFT polymerizations, using methyl methacrylate (MMA) as monomer. Although the in situ addition of TXF promoted a slight reduction of the reaction rate, it did not affect the final particle size distribution of the latex or the molecular weight control exerted by the RAFT agent. The obtained results suggest that in situ incorporation of TXF during the synthesis of polymer NP via RAFT polymerization allows for production of a polymer DDS for different uses, such as the breast cancer treatment.

Dentre as diversas técnicas para obter polímeros de maneira controlada, a técnica de Transferência Reversível de Cadeia por Adição-Fragmentação (RAFT) é tida como uma das mais versáteis, uma vez que é compatível com uma grande quantidade de monômeros, solventes, condições reacionais e sistemas de polimerização. Utilizando essa metodologia, é possível sintetizar polímeros com diversas arquiteturas e com excelente controle do tamanho das cadeias. Neste trabalho, é apresentada uma revisão da técnica de polimerização RAFT em sistemas de miniemulsão. As principais características da técnica de polimerização RAFT e uma ampla revisão dos estudos em miniemulsão são apresentadas, abrangendo mais de 152 referências. Também é abordado nesta revisão o uso da polimerização RAFT em miniemulsão para obtenção de polímeros para aplicações biotecnológicas.

Among the many techniques used to prepare polymers in a controlled manner, reversible addition fragmentation chain transfer polymerization (RAFT) is one of the most versatile, since this technique is compatible with a large number of monomers, solvents, reaction conditions and polymerization systems. Using this methodology, it is possible to synthesize polymers with a variety of architectures and with a high level of control of the molecular weight distribution. In this work, a review of RAFT polymerizations in miniemulsion systems is presented. The main characteristics of the RAFT polymerization technique and a comprehensive review of studies in miniemulsion are presented, comprising more than 152 references. The use of RAFT miniemulsion polymerizaton to obtain polymers for biotechnological applications is also discussed in detail.

A produção em larga escala de materiais poliméricos de elevado interesse industrial, provenientes da polimerização estereoespecífica de olefinas, tornou-se possível depois do advento dos catalisadores Ziegler-Natta. Classificados genericamente em seis gerações, esses catalisadores apresentam diferentes desempenhos em relação ao grau de especificidade do polímero, à atividade e ao controle de morfologia da partícula, o que propicia o desenvolvimento de resinas poliolefínicas com características e propriedades muito variadas. O objetivo principal desse trabalho é revisar e discutir algumas das questões fundamentais que estão relacionadas com as reações de polimerização de olefinas realizadas com catalisadores heterogêneos. Dá-se ênfase particular aos fatores determinantes para a condução apropriada dos processos industriais, como, por exemplo, a fragmentação controlada do catalisador, o fenômeno de replicação das características estruturais do catalisador e o controle da morfologia da partícula de polímero, a importância da prepolimerização e os efeitos relacionados à transferência de calor e massa durante a reação. Discutem-se também aspectos relacionados à modelagem dos sistemas de polimerização e às técnicas experimentais usadas para o estudo do fenômeno de fragmentação das partículas de catalisador.

Large-scale production of polymer materials of high industrial value through stereospecific polymerization of olefins became possible only after the advent of Ziegler-Natta catalysts. Usually grouped into six different generations, these catalysts present distinct activity and allow for production of polymer materials with distinct degrees of stereospecificity, morphology and end-use properties. The main objective of this work is to review and discuss some of the fundamental issues related to olefins polymerization reactions performed with heterogeneous catalysts. Particular emphasis is given to factors that affect the performances of real industrial processes, such as the catalyst fragmentation, the control of the final particle morphology and the morphological replication phenomena, the heat and mass transfer limitations during the polymerization reaction and the prepolymerization stage. Aspects related to the modeling of polymerization reactors and to the experimental study of catalyst fragmentation are also discussed.

This article discusses a survey on the technology of Computational Fluid Dynamics (CFD) in various areas of knowledge and applied particularly in polymers, with scientific articles and patents as sources of information. All the data were mined using “computational”, “fluid” and “dynamic” as keywords. It was observed that private companies are responsible for regulatory filings and universities, research centers and institutes hold patents related to CFD. Moreover, most of the papers selected have authors affiliated with universities and research institutes. From the found papers, 25% are related to polymers, surpassing the percentage of 10% found in the analysis of patents.

Inúmeros processos podem ser utilizados para produção de materiais poliméricos. Cada processo apresenta características peculiares, que permitem produzir resinas com as mais variadas propriedades, visando a diferentes aplicações do material polimérico final. Os processos de polimerização em suspensão são bastante empregados para produção de resinas poliméricas por apresentarem muitas vantagens, como a facilidade de separação, fácil remoção de calor e controle de temperatura e, principalmente, pelos baixos níveis de impureza e de aditivação no produto final. Por isso, processos de polimerização em suspensão são apropriados para obtenção de produtos para aplicações biotecnológicas e médicas, dentre outras. O objetivo principal deste trabalho é apresentar uma discussão dos aspectos fundamentais inerentes aos processos de polimerização em suspensão, visando a uma compreensão do efeito das principais variáveis de processo sobre o desempenho de polimerizações em suspensão. Mostra-se também que a espectroscopia do infravermelho próximo (NIRS) pode ser muito útil para permitir o monitoramento e o controle em tempo real de processos de polimerização em suspensão, para a obtenção de materiais poliméricos com características especiais.

Several processes can be employed for manufacturing polymer materials. Each process presents some intrinsic features that lead to production of resins with peculiar properties, which define the end-use application of the final polymeric material. Suspension polymerization processes are extensively used because of their many advantages, such as the easy separation of the polymer particles, easy removal of the heat of reaction, easy temperature control and low levels of impurities and additives in the final polymer material. For this reason, suspension polymerization processes are suitable to produce polymer resins for biotechnological and medical applications. The main objective of this work is to discuss the fundamental aspects of suspension polymerization processes, focusing upon the effects of the main process variables on the performance of suspension polymerizations. Additionally, it is shown that near infrared spectroscopy (NIRS) can be useful for monitoring and real time control of suspension processes, allowing for production of polymer beads with controlled morphology.