Secondary particle formation in seeded suspension polymerization

Gonçalves, Odinei Hess; Machado, Ricardo Antônio Francisco; Araújo, Pedro Henrique Hermes de; Asúa, José M.

doi:10.1016/j.polymer.2008.11.006

Cited by 29 publications

(20 citation statements)

References 21 publications

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“…3) comparing with the morphologies developed upon synthesis of the bead consisting from a random poly(St-co-MMA) [17] or PS/PMMA core/shell [3]. The morphologies depicted in Fig.…”

Section: Copolymer Formationmentioning

confidence: 99%

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Synthesis of core-shell PS/PMMA expandable particles via seeded suspension polymerization

et al. 2015

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Expandable core-shell beads were synthesized by dosing methyl methacrylate (and styrene) in a constant rate and polymerizing in the presence of polystyrene seeds and pentane. The morphological studies of beads indicated that there were larger poly(methyl methacrylate)-rich domains near the shell. The sizes of these domains were decreased towards the core of the particles. For better surveying the likely structures of domains and the extent of expansion agent diffusion, the beads having the shells formed with copolymerization of styrene and methyl methacrylate in the presence of polystyrene seeds were studied. From the morphological studies, the parallel regular and the onion-like structures were recognizable. In addition, another shell was formed around the dispersed phase showing a complex core/shell structure both in particle and in domain scales. The pentane content in the beads with copolymerized styrene and methyl methacrylate monomers on the polystyrene seeds was increased compared to the beads having the shells of pure poly(methyl methacrylate). This was because the onset of gel effect was longer with adding the styrene to methyl methacrylate monomer hence there was more time for expansion agent to diffuse into the beads. The different amounts of pentane distributed in polystyrene-and poly(methyl methacrylate)-rich phases were discussed in terms of the changes in glass transition temperature of two phases.

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“…3) comparing with the morphologies developed upon synthesis of the bead consisting from a random poly(St-co-MMA) [17] or PS/PMMA core/shell [3]. The morphologies depicted in Fig.…”

Section: Copolymer Formationmentioning

confidence: 99%

“…An important product of suspension polymerization processes is expandable beads, which find applications in many fields such as packaging industry and metal casting technology [1][2][3][4]. Attempts made to find new polymerization methods for producing high quality and selective products led to emersion of seeded polymerization.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of core-shell PS/PMMA expandable particles via seeded suspension polymerization

et al. 2015

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“…91,92 More noticeably, the generic processes also can provide polymer particles with more complex morphologies (e.g. 5 porous particles) and more functions.…”

Section: Suspension Polymerizationsmentioning

confidence: 99%

Particles of polyacetylene and its derivatives: preparation and applications

Huang

et al. 2014

Polym. Chem.

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How to prepare polymeric particles from acetylene and its derivatives, in particular in aqueous media, has remained as a challenging research topic for a rather long period. In recent years, this research area has achieved exciting progress and a variety of novel functional particles have been reported. However, there has not yet a review article exclusively summarizing the progress. This article presents an overview on the advanced particles with emphasis on the preparation and their applications. The state-of-the-art preparation methods fall into two major groups: emulsion, precipitation, suspension polymerization approaches by starting from monomers; and post-treatment of 10 pre-formed polymers (i.e. self-assembly). The polymer particles were investigated in such applications as circuits, sensors, drug release and chiral-related processes for instance asymmetric catalysis, enantioselective crystallization, enantioselective release, amongst many others. The review article is expected to stimulate more unprecedented functional particles derived from acetylene and its derivatives.

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“…Average molar masses were determined by Gel Permeation Chromatography (GPC) using tetrahydrofuran as eluent at 1 mL/min and a refraction index detector. Calibration curve was obtained using polystyrene standards from 580 to 3,800,000 g/mol (GONÇALVES et al, 2009). Logarithmic conversion was used in order to linearize the data and also to compare the values found to those presented by Nijenhuis, Grijpma and Pennings (1992).…”

Section: Methodsmentioning

confidence: 99%

Polimerização do L-lactídeo na Presença de Nitrogênio Gasoso

et al. 2014

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During the ring opening polymerization of L-lactide the presence of water must be avoided since even small amounts can influence negatively on the reaction kinetic behavior. An effective way of removing water from the reaction system should be easy to implement and have comparatively low cost. The objective of the work was to obtain poly (L-lactic acid) at different conditions of temperature and catalyst concentration when gaseous nitrogen is used to purge the reactor comparing the resulting conversion profiles and final average molar masses. Results showed that a long induction period was observed when no gaseous nitrogen was used. It suggests that nitrogen was effective in removing the water from the reaction system since induction periods were not observed when it was injected before polymerization. Depolymerization was avoided when gaseous nitrogen was used resulting in higher molar masses than the case when no purging was carried out. Keywords: Biopolymer. Depolymerization. Gaseous Nitrogen. PLLA. Poly(L-lactic acid). Ring Opening Polymerization. ResumoA presença de água durante a polimerização por abertura de anel de L-lactídeo deve ser completamente evitada. Mesmo presente em pequenas quantidades, a água pode influenciar negativamente o comportamento cinético da reação. A remoção da água de maneira eficaz, a partir do sistema de reação, deve ser de fácil aplicação e com custo relativamente baixo. O objetivo deste trabalho foi obter poli(Lácido lático) em diferentes condições de temperatura e concentração de catalisador, utilizando nitrogênio gasoso para purgar o reator, comparando os perfis de conversão resultantes e as massas molares médias finais. Os resultados demonstraram que um longo período de indução ocorreu quando o nitrogênio gasoso não foi utilizado. Esses resultados sugerem que o nitrogênio possibilita a remoção efetiva da água do sistema de reação, uma vez que os períodos de indução não foram observados quando o gás foi injetado antes da polimerização. O uso de nitrogênio gasoso evitou o processo de despolimerização evidenciado pela obtenção de massas molares mais elevadas do que aquelas em que a purga não foi realizada.

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Secondary particle formation in seeded suspension polymerization

Cited by 29 publications

References 21 publications

Synthesis of core-shell PS/PMMA expandable particles via seeded suspension polymerization

Synthesis of core-shell PS/PMMA expandable particles via seeded suspension polymerization

Particles of polyacetylene and its derivatives: preparation and applications

Polimerização do L-lactídeo na Presença de Nitrogênio Gasoso

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