Mechanisms Of Pvc Thermal Degradation And Stabilization: A Review [mecanismos De Degradação E Estabilização Térmica Do Pvc]

This paper presents a review of PVC thermal degradation and stabilization. The main degradation mechanisms for this resin are shown and correlated to structural defects present in the polymer, as well the stabilization principles

Nonionic Reactive Surfactants In Emulsion Polymerization Of Vinyl Acetate - Vinyl Neodecanoate Latexes: Influence On The Water Barrier Properties [surfactantes Reativos Não-iônicos Em Polimeriza̧ão Em Emulsão De Látices De Acetato De Vinila - Vinil Neodecanoato: Influência Nas Propriedades De Barreira à água]

The paint industry is a huge consumer of latex from emulsion polymerization. The surfactants, essential to the stability of the latex, play a crucial role in the production and application of emulsion polymers. However, they can also have adverse effects on product properties due to their physical adsorption on the polymer particles. The unbound surfactants can migrate through the film toward the interfaces forming aggregates which increase water sensitivity of the film, thus affecting its barrier properties. A promising way to reduce the negative effects of the conventional surfactants is to use polymerizable or reactive surfactants (surfmers) that are covalently linked to the polymer, which avoids its desorption and migration during the film formation. In this work vinyl acetate - vinyl neodecanoate (VeoVa 10®) latexes, stabilized with conventional and reactive nonionic surfactant, were prepared and the performance of these films was evaluated. It was noted that latexes stabilized with nonionic polymerizable surfactants can bring, under certain conditions, better barrier properties.1912230Borsato, D.Moreira, I. & Galão, O. F. - Detergentes Naturals e Sintéticos: um guia técnico, 2o edĩo re- visada, Editora da Universidade Estadual de Londrina, (2004)Gilbert, R.G., (1995) Emulsion Polymerization: A Mechanistic Approach, , Academic PressJonsson, B., Lindman, B., (2001) Surfactants and Polymers in Aqueous Solution, , Wiley Interscience PublicationBuckmann, A.J.P., Nabuurs, T., Overbeek, G.C., (2002) Paints and Coatings Industry, 18, p. 96Buckmann, A. J. P.Nabuurs, T. & Overbeek, G. C. - European Coatings Journal, 6, p.53 (2001)Guyot, A., (2004) Adv. Colloid Interface Sci, 108-109, p. 3Roy, S., Favresse, P., Laschewsky, A., De la Cal, J.C., Asua, J.M., (1999) Macromolecules, 32, p. 5967Schoonbrood, H.A.S., Asua, J.M., (1997) Macromolecules, 30, p. 6034McNamee, W., Grade, J., Non-Migratory Surfactants in Emulsion Polymerization (2005) 9° Congresso Interna- cional de Tintas, ABRAFATI, , São PauloBruyn, H.Miller, M. C.Basset, D. R. & Gilbert, R. G. - Macromolecules, 35, p.8371 (2002)Colombié, D.Sudol, E. D. & El-Aasser M. - Role of Mixed An-/Nonionic Systems of Surfactants in Emulsion Polymerization, in: RC User Forum, Marco Island, USA (1998)Arz, C., (2002) Macromol. Symp, 187, p. 199Butler, L. N.Fellows, C. M. & Gilbert, R. G. - Progress in Organic Coatings, 53, p.112 (2005)Chu, H.H., Piirma, I., (1989) Polymer Bulletin, 21, p. 301Arbina, L. L.Gugliotta, L. M.Barandiaran, M. J. & Asua, J. M. - Polymer, 39, p.4047 (1998)Rogers, C.E., (1965) Physics and Chemistry of the Organic Solid State, 2. , New York, Interscience PublisherIto, F.Makino, K.Ohshima, H.Terada, H. & Omi S. - Physicochem. Eng. Aspects, 233, p.171 (2004)Tadros, T. - Colloids and Interface Science Series, 1, Colloid Stability: The Role of Surface Forces, Part I, Willey-VCH Verlag GmbH & Co. KGaA, Weinheim (2007)Lazaridis, N.Alexopoulos, A. H.Chatzi, E. G. & Kiparissides, C. - Chem. Sci. Eng., 54, p.3251 (1999)Rosen, M. J. - Surfactants and Interfacial Phenomena, iley, New York (1989)Amalvy, J.L., Unzue, M.J., Schoonbrood, H.A.S., Asua, J.M., (2002) J. Polym. Sci.: Part A, 40, p. 2994Visschers, M.Laven, J. & van der Linde, R. - Progress in Org. Coating, 31, p. 311 (1997)De la Cal, J.C., Asua, J.M., (2001) J. Polym. Sci.: Part A, 39, p. 585Aramendia, E.Mallegol, J.Jeynes, C.Barandiaran, M. J.Keddie, J. L. & Asua, J. M. - Langmuir, 19, p.3212 (2003)Murakami, M.M., Correlagao entre morfologia, his- tória de processamento, propriedades fisco-qúmicas e de transporte em filmes de policarbonato (1995) Disserta- ̧ão de Mestrado, , Universidade Federal de São Carlos, BrasilAramendia, E.Barandiaran, M. J.Grade, J.Blease, T. & Asua, J. M. - Langmuir, 21, p.1428 (2005)Lin, F. & Meier, D. J. - Langmuir, 11, p.2726 (1995)Lin, F. & Meier, D. J. - Langmuir, 12, p.2274 (1996)Cannon, L.A., Pethrick, R.A., (2002) Polym, 43, p. 642

Pvc/organically Modified Montmorillonite Nanocomposites: Effects Of Processing And Clay Incorporation Methodology [nanocompósitos De Pvc Com Argila Organicamente Modificada: Efeitos Do Processamento E Do Metodo De Incorpora̧ão Da Argila]

Nanocomposites of poly(vinyl chloride) (PVC) and an organically modified montmorillonite (O-MMT) were prepared using different production approaches to assess possible effects on the degree of clay intercalation/exfoliation. The morphology of the nanocomposites was studied using X ray diffratometry and transmission electron microscopy. Tensile properties and static thermal stability were also evaluated. Hybrid intercalated/partially exfoliated nanocomposites were obtained, regardless of whether the PVC compound was processed from the powder (dry blend) or granulated (extruded) samples, or of the methodology used for incorporation of O-MMT into the PVC compound (directly in the intensive mixer or pre-exfoliated in a hot mixture of DIDP/ESO). The plasticizers, present in the flexible PVC compound, exerted an important role in the process of intercalation and exfoliation of the clay, helping the formation of the nanocomposites.19119(2008) 2008 world vinyls analysis, , Chemical Market Associates, Chemical Market Associates, Inc, HoustonChow, G.-M., Kurihara, L.K., Chemical synthesis and processing of nanostructured powders and films (2002) Nanostructured materials: Processing, properties and potential applications, , C. C. Kock ed, Noyes Publications, NorwichJordan, J.Jacob, K. I.Tannenbaum, R.Sharaf, M. A. & Jasiuk, I. - Materials Science and Engineering: A, 393, p.1 (2004)Schmidt, D.Shah, D. & Giannelis, E. P. - Current Opinion in Solid State & Materials Science, 6, p.205 (2002)Yang, F., Ou, Y., Yu, Z., (1998) Journal of Applied Polymer Science, 69, p. 355Gilman, J.W., (1999) Applied Clay Science, 15, p. 31Giannelis, E.P., (1992) Materials and Design, 13, p. 100Lan, T.Kaviratna, P. D. & Pinnavaia, T. J. - Chemistry of Materials, 6, p.573 (1994)Wang, Z.Lan, T. & Pinnavaia, T. J. - Chemistry of Ma- terials, 8, p.2200 (1996)Alexandre, M., Dubois, P., (2000) Materials Science and Engineering: R, 28, p. 1Ray, S.S., Okamoto, M., (2003) Progress in Polymer Science, 28, p. 1539Paul, D.R., Robeson, L.M., (2008) Polymer, 49, p. 3187Pavlidou, S., Papaspyrides, C.D., (2008) Progress in Polymer Science, 33, p. 1119Utracki, L.A., (2004) Clay-containing polymeric nanocompo- sites, 1. , v, Rapra Technology Ltd, ShropshireRodolfo Jr., A., Mei, L.H.I., (2007) Polímeros: Ciência e Tecnologia, 17, p. 263Wang, D.Parlow, D.Yao, Q. & Wilkie, C. A. - Journal of Vinyl and Additive Technology, 7, p.203 (2001)Schaefer, D.W., Justice, R.S., (2007) Macromolecules, 40, p. 8501Yalcin, B., Cakmak, M., (2004) Polymer, 45, p. 6623Kovarova, L.Kalendova, A.Gerard, J.-F.Malac, J.Simonik, J. & Weiss, Z. - Macromolecular Symposia, 221, p.105 (2005)Peprnicek, T.Duchet, J.Kovarova, L.Malac, J.Gerard, J.-F. & Simonik, J. - Polymer Degradation and Stability, 91, p.1855 (2006)Peprnicek, T.Kalendova, A.Pavlova, E.Simonik, J.Duchet, J. & Gerard, J.-F. - Polymer Degradation and Stability, 91, p.3322 (2006)Francis, N., Schmidit, D.F., PVC/layered silicate nanocomposites: Preparation, characterization, and properties (2007) ANTEC, p. 1238. , Cincinnati, EUA, pKalendova, A.Kovarova, L.Malac, Z.Malac, J.Vaculik, J.Hrncirik, J. & Simonik, J. - Modified clay in polyvinyl chloride (PVC), in: ANTEC 2002, Saõ Francisco - EUA (2002)Southern Clay Products - Cloisite® 30B - Typical physical properties bulletin, disponível em www.scprod. com. Acesso em 4 fev. 2008Faulkner, P.G., (1975) Journal of Macromolecular Science - Physics B, 11, p. 251Rabinovitch, E.B., Summers, J., (1980) Journal of Vinyl Technology, 2, p. 165Marques, R.P., Covas, J.A., (2003) Processing characteristics of U-PVC compounds, , Companhia Industrial de Resinas Sintéticas, EstarrejaFillot, L.-A.Hajji, P.Gauthier, C. & Masenelli-Varlot, K. - Journal of Vinyl and Additive Technology, 12, p.98 (2006)Alves, J.P.D., Rodolfo Jr., A., (2006) Polímeros: Ciência e Tecnologia, 16, p. 165Fornes, T. D.Yoon, P. J.Keskkula, H. & Paul, D. R. - Polymer, 42, p.9929 (2001

Preparation of silica with controlled pore sizes for enzyme immobilization

A simple method for the preparation of silica with controlled pore size, for use as a support for the immobilization of enzymes, is described in this article. Using sodium silicate and hydrochloric acid, a microporous silica was obtained that was then submitted to a hydrothermal treatment, resulting in macroporous silica suitable for enzyme immobilization. Suitability of the macroporous silica as a support depends on the method chosen for its preparation, which will determine pore volume and the effect of hydrothermal treatment on pore size. The pore volume of the support was 0.8-0.9 cc/g and the average pore size, controlled by the hydrothermal treatment, was in the range of 16 to 75 nm. The enzyme amyloglucosidase was used for the immobilization studies.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Preparation of silica with controlled pore sizes for enzyme immobilization

A simple method for the preparation of silica with controlled pore size, for use as a support for the immobilization of enzymes, is described in this article. Using sodium silicate and hydrochloric acid, a microporous silica was obtained that was then submitted to a hydrothermal treatment, resulting in macroporous silica suitable for enzyme immobilization. Suitability of the macroporous silica as a support depends on the method chosen for its preparation, which will determine pore volume and the effect of hydrothermal treatment on pore size. The pore volume of the support was 0.8-0.9 cc/g and the average pore size, controlled by the hydrothermal treatment, was in the range of 16 to 75 nm. The enzyme amyloglucosidase was used for the immobilization studies.7177Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Study Of The Influence Of Plasticizers On The Thermal And Mechanical Properties Of Poly(3-hydroxybutyrate) Compounds

The influence of four types of plasticizers, dioctyl phthalate (DOP), dioctyl adipate (DOA), triacetyl glycerol (TAG) and polyadipate (PA), in the thermal and mechanical properties of Poly(3-hydroxybutyrate) (PHB), a highly crystalline biodegradable polyester, was evaluated in this work. The plasticizers were introduced alone or mixtures of them, using concentrations that varied from 5 to 30% wt. Their influence in some important polymer parameters as Tg, Tm and degree of crystallinity, and on its mechanical behavior, elongation and tensile strain were investigated. The best results were obtained for the sample with 30% TAG and that one using a binary mixture of plasticizers PA 20% and TAG 10%.1973344Braunneg, G., Lefebvre, G., Genser, K.F., Polyhydroxyalkanoates, biopolyesters from renewable resources: Physiological and engineering aspects (1998) J. of Biotechnol., 65, pp. 127-161Stanislav, M., Chiellini, E., Mei, L.H.I., (1999) Proceedings of the Environmentally Degradable Polymers in Brazil. International Workshop on Recyclable and Environmentally Degradable Polymers in Latin America WEDPLA' 98-ICS-UNIDO, , Campinas, Brazil, NovQi, Q., Rehn, B.H.A., Steinbüchee, A., Synthesis of Poly(3-hydroxyalkanoates) in Escherichia coli expressing the PHA synthase gene phaC2 from Pseudomonas aeruginosa: Coparasion of PhaC1 and PhaC2 (1997) FEMS Microbiology Letters, 157, pp. 155-162Marchessault, R.H., Coulombe, S., Marikawa, H., Okamura, K., Revol, J.F., Solid State Properties of Poly-β-Hydroxybutyrate and its Oligomers (1981) Can. J. Chem., 59, pp. 38-44Savenkova, L., Gercberga, Z., Nikolaeva, V., Dzene, A., Bibers, I., Kalnin, M., Mechanical Properties and Biodegradation Characteristics of PHB-Based Films (2000) Process Biochemistry, 35, pp. 573-579Konning, G.J.M., Lemstra, P.J., Crystallization phenomena in bacterial poly(3-hydroxybutyrate): 2-Embrittlement and rejuvenation (1993) Polymer., 34, pp. I9Sharma, R., Ray, A.R., Polyhydroxybutyrate, Its Copolymers and Blends (1995) J.M.S.-Rev. Macromol. Chem. Phys., C35 (2), pp. 327-359Holmes, P.A., Applications of PHB - A microbially produced biodegradable thermoplastic (1985) Phys. Technol., 16, pp. 32-33Yoshie, N., Nakasato, K., Fujiwara, M., Kasuya, K., Abe, H., Doi, Y., Inoue, Y., Effect of Low Molecular Weight Additives on Enzymatic Degration of Poly(3-hydroxybutyrate) (2000) Polymer, 41, pp. 3227-3234Hocking, P.J., Revol, J.F., Macgessault, R.H., Single crystal, crystalline morphology of synthetic racemic poly(β-hydroxybutyrate) (1996) Macromolecules, 29, pp. 2467-2471Ikejima, T., Ioue, Y., Crystallization behavior and environmental biodegradability of the blend films of poly(β-hydroxybutiric acid) with chitin and chitosan (2000) Carbohydrate Polymers, 41, pp. 351-356Kim, M.-N., Lee, A.-R., Lee, K.-H., Chin, I.-J., Yoon, J.-S., Biodegradability of poly(3-hydroxybutyrate) blended with poly(ethylene-co-vinyl acetate) or poly(ethylene oxide) (1999) European Polymer Journal, 35, pp. 1153-1158Ramsay, B.A., Lomaliza, K., Chavarie, C., Dubé, B., Bataille, P., Ramsay, J.A., Production of poly (3-hydroxybutiric-co-3-hydroxyvaleric) acids (1990) Appl. Environ. Microbiol., 56, pp. 2093-2098Saad, R.G., Mansour, A.A., Hamed, A.H., Dieletric investigation of cold crystallization of poly(3-hydroxybutyrate) (1997) Polymer, 16 (38), pp. 4091-4096Yoshie, N., Nakato, K., Fujiwara, M., Kasuya, K., Abe, H., Doi, Y., Inoue, Y., Effect of low molecular weight additives on enzymatic degradation ofpoly(3-hydroxybutyrate) (2000) Polymer, 41, pp. 3227-3234Bueche, F., Physical Properties of Polymers (1962) Inter Science Publ

Performance Development Requirements For Elastomers Of Electric Power Network Insulators

The aim of this work was to present some results of the characterization of polymers insulators during their degradation, which are used in transmission threads of 69 kV. The intention was to develop performance requirements for these products. A comparative study was done among products collected in the experimental field and the new products artificially aged in laboratory, according to the methodologies applied to polymers. Elastomeric silicon and ethylene-propylene diene rubber (EPDM) blankets were also prepared in the same way as the insulating and investigated. Based on the obtained results, it was suggested some performance requirements that may be utilized during the acquisition of these products by the dealership. In this paper, the results that induced the adoption of the performance requirements studied will be presented, in addition to the standards already utilized for product qualification. © 2005 Elsevier B.V. All rights reserved.162-163SPEC. ISS.102108Rossi, J.A.D., (2004) Desenvolvimento de Sensores, , CPqD, CampinasBrito, F., (2003) Technical Relatory, , Unicamp-FEE, CampinasMello, D.R., (2003) Technical Relatory, , Cepel, Rio de Janeir

Water And Drug Transport In Radiation-crosslinked Poly(2-methoxyethylacrylate-co-dimethyl Acrylamide) And Poly(2-methoxyethylacrylate-co-acrylamide) Hydrogels

Hydrogels of poly(N,N′-dimethylacrylamide-co-2-methoxyethylacrylate) and poly(acrylamide-co-2-methoxyethylacrylate) have been synthesized by radiation polymerization in dimethylformamide solution with trimethylolpropane trimethacrylate as a crosslinker. In this work, some investigations on the in vitro release of gentamicin sulphate, an antibiotic entrapped in the hydrogels, are reported. The kinetics of drug release from hydrogels matrices were examined and the results indicate that the release for the proposed geometry practically occurs in the first 24h. The fractional cumulative release of the drug from the DMAA/MOEA matrices is linear when plotted against the square root of time, pointing out a Fickian process. On the other hand, AAm/MOEA matrices showed an initial non-Fickian behaviour, probably indicating a comparable rates of Fickian diffusion and polymer relaxation. © 2003 Elsevier Science Ltd. All rights reserved.662155159Caliceti, P., Salmaso, S., Lante, A., Yoshida, M., Katakai, R., Martellini, F., Mei, L.H.I., Carenza, M., Controlled release of biomolecules from temperature-sensitive hydrogels prepared by radiation polymerization (2001) J. Controlled Release, 75, pp. 173-181Crank, J., Park, G.S., (1968) Diffusion in Polymers, pp. 1-37. , Academic Press, LondonEl-Ejmi, A.A.S., Huglin, M.B., Characterization of N,N-dimethylacrylamide/2-methoxy-ethylacrylate copolymers and phase behaviour of their thermotropic aqueous solutions (1996) Polym. Int., 39, pp. 113-119El-Ejmi, A.A.S., Huglin, M.B., Behaviour of Poly(N,N-dimethylacrylamide-co-2-methoxyethylacrylate) in non-aqueous solution and LCST behaviour in water (1997) Eur. Polym. J., 33, pp. 1281-1284Galaev, I.Yu., "Smart" polymers in biotechnology and medicine (1995) Russ. Chem. Rev., 64, pp. 471-489Hoffman, A.S., "Intelligent" polymers in medicine and biotechnology (1995) Macromol. Symp., 98, pp. 645-664Korsmeyer, R.W., Diffusion controlled systems: Hydrogels (1991) Polymers for Controlled Drug Delivery, pp. 15-37. , P.J. Tarcha. Boca Raton, FL: CRS PressKost, J., Langer, R., Responsive polymeric delivery systems (2001) Adv. Drug Delivery Rev., 46, pp. 125-148Lee, P.I., Kinetics of drug release from hydrogel matrices (1985) J. Controlled Release, 2, pp. 277-288Martellini, F., Mei, L.H.I., Baliño, J.L., Carenza, M., Swelling and water transport in temperature-sensitive hydrogels based on 2-methoxyethylmethacrylate (2002) Radiat. Phys. Chem., 63, pp. 29-33Mueller, K.F., (1991) Thermotropic Copolymer Hydrogels from N,N-dimethylacrylamide and Methoxy-ethyl (Methyl) Acrylate, , US Patent No. 5 057 569, New YorkMueller, K.F., Thermotropic aqueous gels and solutions of N,N-dimethylacrylamide-acrylate copolymers (1992) Polymer, 33, pp. 3470-3476Okano, T., Yoshida, R., Polymers for pharmaceutical and biomolecular engineering (1993) Biomedical Applications of Polymeric Materials, pp. 407-428. , T. Tsuruta. Boca Raton, FL: CRC PressRitger, P.L., Peppas, N.A., A simple equation for description of solute release II. Fickian and anomalous release from swellable devices (1987) J. Controlled Release, 5, pp. 37-42Rosiak, J.M., Ulanski, P., Rzeznicki, A., Hydrogels for biomedical purposes (1995) Nucl. Instrum. Meth. Phys. Res. B, 105, pp. 335-339San Roman, J., Gallardo, A., Levenfeld, B., New polymers for biomedical applications - Synthesis and characterization of acrylic systems with pharmacological activity (1994) Macromol. Symp., 84, pp. 145-158Souza, R.G., Magalhães, W.F., Freitas, R.F.S., Glass transition and thermal stability of poly(N-isopropylacrylamide) gels and some of their copolymers with acrylamide (1998) Polym. Degrad. Stab., 61, pp. 275-281Taylor, L.D., Cerankowski, L.D., Preparation of films exhibiting a balanced temperature dependence to permeation by aqueous solutions - A study of lower consolute behavior (1975) J. Polym. Sci. Polym. Chem. Ed., 13, pp. 2551-2570Uhrich, K.E., Canizzaro, S.M., Langer, R.S., Shakesheff, K.M., Polymeric systems for controlled release (1999) Chem. Rev., 99, pp. 3181-3198Yoshida, M., Safranj, A., Omichi, H., Polymerization, self-bridging, and degradation of acryloyl- and methacryloyl-L-proline methyl esters induced by radiation and characteristics of gel swelling (1996) Macromolecules, 29, pp. 2321-2323Zhang, X., Wyss, U.P., Pichora, D., Goosen, M.F.A., Biodegradable controlled antibiotic release devices for osteomyelitis: Optimization of release properties (1994) J. Pharm. Pharmacol., 46, pp. 718-72

Synthesis, Functionalization And Characterization Of Polystyrene In Emulsion For Utilization In Immunological Assay

Polystyrene latex microspheres were synthesized using the method of emulsion polymerization. Steps included nitration, amination and diazotization. Each step was accompanied through Fourier transform infrared spectroscopy. Particle size distribution was examined in a submicrom particule analyzer and scanning electron micrograph. Bovine serum albumin (BSA)-sensitized latex agglutinated in a few seconds, in the presence of a rabbit serum containing specific antibodies to BSA. The importance of optimizing some variables during the synthesis was emphasized for the success of the latex's application in immunological assays.22