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Título:
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Moulded polypropylene foams produced using chemical or physical blowing agents: structure–properties relationship
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Autor/a:
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Saiz-Arroyo, Cristina; Saja, José Antonio de; Velasco Perero, José Ignacio; Rodríguez-Pérez, Miguel Ángel
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Otros autores:
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Universitat Politècnica de Catalunya. Departament de Ciència dels Materials i Enginyeria Metal·lúrgica; Universitat Politècnica de Catalunya. POLYCOM - Polimers i compòsits: tecnologia |
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Abstract:
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Polypropylene (PP) foams have become
essential items due to their excellent properties. Nevertheless,
obtaining net-shaped PP foams with medium relative
densities is a complicated issue. In this article, two
processes able to produce moulded PP foams in this density
range are presented. One of them is based on a modification
of the pressure quench foaming method and therefore
uses a physical blowing agent (CO2). The second one is the
improved compression moulding technique which uses a
chemical blowing agent (azodicarbonamide). PP foams
with relative densities in the range between 0.25 and 0.6
and cylindrical shape were prepared using these foaming
techniques. A common PP grade (instead a highly branched
one) was used to obtain the samples, showing, that by
combining the appropriate foaming technique, the adequate
moulds, suitable blowing agent and proper foaming
parameters, net-shaped PP foams with excellent properties
can be produced starting from a conventional PP grade.
Samples were characterized by analyzing their cellular
structure and their mechanical properties. Results have
showed that depending on the chosen foaming route isotropic
or anisotropic structures with cell sizes ranging from 40 to 350 lm and open cell content in the range between 0
and 65% can be obtained. Moreover, mechanical properties
are highly influenced by the production route and chemical
composition of the foams. For instance, the stiffer materials
at relative densities higher than 0.4 are the ones produced
using the chemical blowing agent while at relative densities
lower than 0.4 are the ones produced using the physical
blowing agent. |
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Abstract:
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Peer Reviewed |
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Materia(s):
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-Àrees temàtiques de la UPC::Enginyeria dels materials::Materials plàstics i polímers
-Foam
-Polypropylene
-Escumes (Indústria química)
-Polipropilè |
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Derechos:
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Tipo de documento:
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Artículo - Versión publicada
Artículo |
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