Papers by Marcus Dal Pizzol
blends of polystyrene and poly lactic acid. are described polymer blends of polystyrene (PS) and ... more blends of polystyrene and poly lactic acid. are described polymer blends of polystyrene (PS) and poly lactic acid (PLA) having add a compatibilizing agent, preferably a copolymer PLA-PS block. compatibilizers such agents act by controlling the phase separation between the components of the blend, not allowing excessive growth of the polystyrene domains dispersed in the PLA matrix, leading to obtain blends with good thermal and mechanical resistance.
Great improvements in the environmental stress cracking resistance (ESCR) of high-impact polystyr... more Great improvements in the environmental stress cracking resistance (ESCR) of high-impact polystyrene grades (HIPS) have been recently achieved, granting their use in new applications in fatty food packaging. This work focuses on the correlation among composition, morphology and ESCR of three commercial ESCR HIPS grades and four HIPS batches prepared in lab scale. The morphology of samples was analyzed by low angle light laser light scattering (LALLS) and transmission electron microscopy (TEM), and they were submitted to flexural ESCR tests with two fatty agents. Largesize rubber particles (dispersed phase) and high molecular weight PS (matrix phase) were confirmed as the key parameters to obtain HIPS with good ESC resistance. Besides, very high viscosity polybutadiene and high cis content (> 96% cis isomer) were decisive to obtain improved ESCR to fatty agents. Optimal ESCR regarding the fatty agents was obtained for HIPS containing around 7.5% of such high cis-polybutadiene, wit...
Polymer Degradation …, 2009
... optical properties. These pro-oxidant-activated materials have been used as mulch films, in a... more ... optical properties. These pro-oxidant-activated materials have been used as mulch films, in agriculture [10], and as retail shopping bags and garbage bags [5] and [11], among many other applications. Biodegradable polymers ...
Great improvements in the environmental stress cracking resistance (ESCR) of high-impact polystyr... more Great improvements in the environmental stress cracking resistance (ESCR) of high-impact polystyrene grades (HIPS) have been recently achieved, granting their use in new applications in fatty food packaging. This work focuses on the correlation among composition, morphology and ESCR of three commercial ESCR HIPS grades and four HIPS batches prepared in lab scale. The morphology of samples was analyzed by low angle light laser light scattering (LALLS) and transmission electron microscopy (TEM), and they were submitted to flexural ESCR tests with two fatty agents. Large-size rubber particles (dispersed phase) and high molecular weight PS (matrix phase) were confirmed as the key parameters to obtain HIPS with good ESC resistance. Besides, very high viscosity polybutadiene and high cis content (> 96% cis isomer) were decisive to obtain improved ESCR to fatty agents. Optimal ESCR regarding the fatty agents was obtained for HIPS containing around 7.5% of such high cis-polybutadiene, wi...
Polímeros, 2001
A tenacificação da matriz vítrea de poliestireno (PS) pela adição de borracha polibutadiênica, qu... more A tenacificação da matriz vítrea de poliestireno (PS) pela adição de borracha polibutadiênica, que tem como conseqüência um aumento de sua resistência ao impacto, origina um polímero com características singulares, o Poliestireno de Alto Impacto (HIPS). Durante a polimerização in situ de estireno em uma solução de borracha, ocorre a formação de cadeias graftizadas de poliestireno no polibutadieno, as quais aumentam a interação interfacial borracha-PS. O HIPS é um material com ampla aplicação na indústria de embalagens e, principalmente, em gabinetes de refrigeradores, a chamada linha branca. O objetivo deste artigo é destacar e discutir as características estruturais e morfológicas do HIPS e a implicação destas na determinação de suas propriedades. Também foram revisadas as técnicas comumente utilizadas na caracterização morfológica e estrutural do HIPS.
Polimeros Ciencia E Tecnologia, 2008
Poliestireno de alto impacto (HIPS) é uma blenda polimérica clássica de reator produzida por poli... more Poliestireno de alto impacto (HIPS) é uma blenda polimérica clássica de reator produzida por polimerização in-situ de estireno em solução com borracha butadiênica. Na literatura, está bem estabelecida a importância do tamanho de partícula e da densidade da ligação cruzada da borracha na capacidade de cavitação e no controle dos mecanismos de tenacificação na matriz estirênica. No presente trabalho as técnicas de microscopia eletrônica de transmissão (MET) e espalhamento de luz laser de baixo ângulo (LALLS) foram empregadas para observar a distribuição do tamanho de partícula, e a análise digital de imagem foi aplicada para quantificar os parâmetros morfológicos nas micrografias. Medidas do tamanho de partícula e da fração aparente volumétrica de partícula foram feitas para diferentes espessuras na MET e comparadas com o parâmetro estatístico D [4,3] obtido na LALLS.
Journal of Applied Polymer Science, Oct 5, 2012
The dispersion of ethylene-propylene-diene terpolymer (EPDM) rubber in a polystyrene (PS) matrix ... more The dispersion of ethylene-propylene-diene terpolymer (EPDM) rubber in a polystyrene (PS) matrix is an alternative for improving the weathering resistance of high-impact polystyrene (HIPS), which commonly contains polybutadiene as an impact modifier. However, EPDM and PS are immiscible, and compatibilizers are required to improve the final properties. In this study, EPDM-PS blends were prepared by melt mixing, and the compatibilizing effects of two block copolymers on these blends was studied. The materials were analyzed by scanning electron microscopy, tensile and impact tests, and exposure to UV light for 20 days. The addition of styrene-butadiene-styrene block copolymer (SBS) and styrene-ethylene-co-butylenestyrene block copolymer (SEBS) improved the dispersion of EPDM in the PS matrix. The compatibilized blends showed lower tensile properties, but an important increase in the impact strength was observed compared to the noncompatibilized blend. With regard to the impact strength, SBS was more effective than SEBS as a compatibilizer. All of the blends showed higher UV resistances than the commercial HIPS, and the best performance was observed in the blends compatibilized with SEBS. These results are discussed and explained in terms of the blends' morphologies and chemical compositions. V
Journal of Applied Polymer Science, 2001
Three samples of ethylene-octadecene copolymers having different quantitative composition were an... more Three samples of ethylene-octadecene copolymers having different quantitative composition were analyzed structurally and in terms of their thermal behavior. The samples were fractionated by temperature rising elution fractionation, presenting different chemical composition distributions (CCD) that are essentially the result of the proportion of incorporated octadecene. The CCD profiles were relatively wide for samples generated by metallocene catalysts. The analyses of the fractions showed that the melting and crystallization temperatures decrease with increasing comonomer incorporation, but this relation is affected by the average molecular weight of the chains. The melting thermograms of those fractions having higher proportions of octadecene may be divided into two characteristic regions: the first one, at a higher temperature, originates from the melting of the least modified chains, which crystallize more perfectly. The second one is formed by the melting of chains having a hig...
Resumo: Neste trabalho, utilizou-se um planejamento experimental e a análise estatística dos resu... more Resumo: Neste trabalho, utilizou-se um planejamento experimental e a análise estatística dos resultados para investigar a influência de variáveis de polimerização (iniciador, transferidor de cadeia e solvente) e do processo de devolatilização (temperatura e tempo) sobre a morfologia e resistência química sob tensão, ESCR, do HIPS. Determinou-se o tamanho e a distribuição dos tamanhos das partículas de PB nas amostras de HIPS através de espalhamento de luz laser de baixo ângulo, o grau de inchamento do gel em tolueno, monômero residual por cromatografia gasosa e ESCR (ataque a manteiga) por ensaios de tensão-deformação. Palavras-chave: Poliestireno de alto impacto, partícula de borracha, morfologia, devolatilização
Polímeros
Resumo: A tenacificação da matriz vítrea de poliestireno (PS) pela adição de borracha polibutadiê... more Resumo: A tenacificação da matriz vítrea de poliestireno (PS) pela adição de borracha polibutadiênica, que tem como conseqüência um aumento de sua resistência ao impacto, origina um polímero com características singulares, o Poliestireno de Alto Impacto (HIPS). Durante a polimerização in situ de estireno em uma solução de borracha, ocorre a formação de cadeias graftizadas de poliestireno no polibutadieno, as quais aumentam a interação interfacial borracha-PS. O HIPS é um material com ampla aplicação na indústria de embalagens e, principalmente, em gabinetes de refrigeradores, a chamada linha branca. O objetivo deste artigo é destacar e discutir as características estruturais e morfológicas do HIPS e a implicação destas na determinação de suas propriedades. Também foram revisadas as técnicas comumente utilizadas na caracterização morfológica e estrutural do HIPS.
Great improvements in the environmental stress cracking resistance (ESCR) of high-impact polystyr... more Great improvements in the environmental stress cracking resistance (ESCR) of high-impact polystyrene grades (HIPS) have been recently achieved, granting their use in new applications in fatty food packaging. This work focuses on the correlation among composition, morphology and ESCR of three commercial ESCR HIPS grades and four HIPS batches prepared in lab scale. The morphology of samples was analyzed by low angle light laser light scattering (LALLS) and transmission electron microscopy (TEM), and they were submitted to flexural ESCR tests with two fatty agents. Large-size rubber particles (dispersed phase) and high molecular weight PS (matrix phase) were confirmed as the key parameters to obtain HIPS with good ESC resistance. Besides, very high viscosity polybutadiene and high cis content (> 96% cis isomer) were decisive to obtain improved ESCR to fatty agents. Optimal ESCR regarding the fatty agents was obtained for HIPS containing around 7.5% of such high cis-polybutadiene, wi...
Resumo: Neste trabalho, utilizou-se um planejamento experimental e a análise estatística dos resu... more Resumo: Neste trabalho, utilizou-se um planejamento experimental e a análise estatística dos resultados para investigar a influência de variáveis de polimerização (iniciador, transferidor de cadeia e solvente) e do processo de devolatilização (temperatura e tempo) sobre a morfologia e resistência química sob tensão, ESCR, do HIPS. Determinou-se o tamanho e a distribuição dos tamanhos das partículas de PB nas amostras de HIPS através de espalhamento de luz laser de baixo ângulo, o grau de inchamento do gel em tolueno, monômero residual por cromatografia gasosa e ESCR (ataque a manteiga) por ensaios de tensão-deformação. Palavras-chave: Poliestireno de alto impacto, partícula de borracha, morfologia, devolatilização Abstract: In this work, an experimental design and statistical analysis of results were used to investigate the influence of variables of polymerization (initiator, chain transfer and solvent) and devolatilization conditions (temperature and time) on the morphology and env...
The influence of the rubber particle size distribution on environmental stress cracking resistanc... more The influence of the rubber particle size distribution on environmental stress cracking resistance (ESCR) of two different high impact polystyrene (HIPS) was investigated. The samples were synthesized under the same reaction conditions, except the stirring speed after the phase inversion between PB and PS. This results in a sample A with rubber particles size larger and a sample B with particles size smaller determined by low-angle laser-light scattering (LALLS) technique. Blends of sample A and B (A/B) in a proportion 100/0, 75/25, 50/50, 25/75 and 0/100 were prepared in the melt blended. The blends were characterized by transmission electron microscopy and ESCR tests for oleic mixture. The blend with higher amount of small particle size shows a drastic decrease on elongation after the contact with the oleic mixture. At this way, it was possible to evaluate the effect of the rubber particle size on ESCR, independently of the other variables.
This study describes the preparation and characterization of PLLA/HIPS bioblends compatibilized b... more This study describes the preparation and characterization of PLLA/HIPS bioblends compatibilized by PS-b-PLA block copolymer. Blends with compositions of 60 PLLA:40 HIPS using 5% compatibilizer were obtained by melt mixing. The PLA-b-PS was obtained by atom transfer radical polymerization (ATRP) using PLA-Br as macroinitiator. PLA-Br was synthesized using 2,2,2-tribromoethanol as initiator through ring opening polymerization of lactide. The blends were characterized by mechanical properties (tensile tests) and morphology. PLLA/HIPS 60/40 bioblends exhibited some control over morphology when was added 5% PLA-b-PS block copolymer.
Polímeros, 2008
Poliestireno de alto impacto (HIPS) é uma blenda polimérica clássica de reator produzida por poli... more Poliestireno de alto impacto (HIPS) é uma blenda polimérica clássica de reator produzida por polimerização in-situ de estireno em solução com borracha butadiênica. Na literatura, está bem estabelecida a importância do tamanho de partícula e da densidade da ligação cruzada da borracha na capacidade de cavitação e no controle dos mecanismos de tenacificação na matriz estirênica. No presente trabalho as técnicas de microscopia eletrônica de transmissão (MET) e espalhamento de luz laser de baixo ângulo (LALLS) foram empregadas para observar a distribuição do tamanho de partícula, e a análise digital de imagem foi aplicada para quantificar os parâmetros morfológicos nas micrografias. Medidas do tamanho de partícula e da fração aparente volumétrica de partícula foram feitas para diferentes espessuras na MET e comparadas com o parâmetro estatístico D[4,3] obtido na LALLS.
Polímeros, 2001
A tenacificação da matriz vítrea de poliestireno (PS) pela adição de borracha polibutadiênica, qu... more A tenacificação da matriz vítrea de poliestireno (PS) pela adição de borracha polibutadiênica, que tem como conseqüência um aumento de sua resistência ao impacto, origina um polímero com características singulares, o Poliestireno de Alto Impacto (HIPS). Durante a polimerização in situ de estireno em uma solução de borracha, ocorre a formação de cadeias graftizadas de poliestireno no polibutadieno, as quais aumentam a interação interfacial borracha-PS. O HIPS é um material com ampla aplicação na indústria de embalagens e, principalmente, em gabinetes de refrigeradores, a chamada linha branca. O objetivo deste artigo é destacar e discutir as características estruturais e morfológicas do HIPS e a implicação destas na determinação de suas propriedades. Também foram revisadas as técnicas comumente utilizadas na caracterização morfológica e estrutural do HIPS.
Polymer Degradation and Stability, 2009
... optical properties. These pro-oxidant-activated materials have been used as mulch films, in a... more ... optical properties. These pro-oxidant-activated materials have been used as mulch films, in agriculture [10], and as retail shopping bags and garbage bags [5] and [11], among many other applications. Biodegradable polymers ...
Journal of Materials Science, 2008
High impact polystyrene (HIPS) is a classical reactor polymer blend produced by in situ polymeriz... more High impact polystyrene (HIPS) is a classical reactor polymer blend produced by in situ polymerization of styrene in solution with polybutadiene rubber. The importance of the particle size and rubber crosslink density on the particle cavitation capability and the controlling of toughening mechanisms in the styrenic matrix is well established in current literature. In the present work, the role of the rubber particle on the HIPS toughness has been investigated for two commercial grades with low and high cis polybutadiene. Transmission electron microscopy (TEM) was employed for observation of particle size distribution and digital imaging applied for quantitative analysis of the micrographs. Measurements of apparent volume fraction and average particle size were determined in TEM images for both grades, while the gel content and swelling index were employed to evaluate the effect of the polybutadiene cis isomer on the rubber crosslink density. Grade morphology and crosslink effects on mechanical properties were assessed by slow three-point bending and uniaxial tensile testing. The results illustrate that polybutadiene cis content in HIPS grades has strong influence on the mechanical properties, particularly affecting yielding and energy to failure. Accordingly, it was observed that HIPS grades with equivalent average particle size and apparent volume fractions present a much higher energy to failure and a lower yield stress with high cis content polybutadiene when compared to their lower cis polybutadiene counterparts.
Journal of Applied Polymer Science, 2001
ABSTRACT Three samples of ethylene-octadecene copolymers having different quantitative compositio... more ABSTRACT Three samples of ethylene-octadecene copolymers having different quantitative composition were analyzed structurally and in terms of their thermal behavior. The samples were fractionated by temperature rising elution fractionation, presenting different chemical composition distributions (CCD) that are essentially the result of the proportion of incorporated octadecene. The CCD profiles were relatively wide for samples generated by metallocene catalysts. The analyses of the fractions showed that the melting and crystallization temperatures decrease with increasing comonomer incorporation, but this relation is affected by the average molecular weight of the chains. The melting thermograms of those fractions having higher proportions of octadecene may be divided into two characteristic regions: the first one, at a higher temperature, originates from the melting of the least modified chains, which crystallize more perfectly. The second one is formed by the melting of chains having a high degree of comonomer incorporation, which melt in a diffuse manner over a wide range of temperatures. It is probable that the morphology of the crystals formed in this region does not follow the folded chain model, and are better represented by a model involving the alignment of chain segments (bundling). © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 221–227, 2001
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Papers by Marcus Dal Pizzol