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News Article | November 23, 2016
Site: www.newsmaker.com.au

Redispersible Polymer Powder is a free-flowing organic polymer powder, produced through the spray drying of a wide range of monomers such as vinyl acetate, vinyl versatate, ethylene, acrylate, and styrene butadiene. Redispersible Polymer Powder is produced in two stages. In the first stage, water-based emulsion polymerization technology is used to convert various monomers to liquid dispersion. In the second step, water-based dispersion is used after some modification to produce free-flowing redispersible polymer powder through spray drying technology. Redispersible polymer powder improves the plasticity adhesion of tile cement, gypsum plaster, and self-leveling compounds. Redispersible polymer powders are used mainly in diverse construction chemical applications such as external thermal insulation composite systems, construction and tile adhesives, screeds, self-leveling flooring compounds, plasters, repair mortars, grouts, and cementitious sealing slurries. Demand for redispersible polymer is continuously increasing due to its benefits in the construction industry such as better water retention and workability, strong strength development of the mortar, higher flexural strength and flexibility, and strong impact and abrasion resistance. On the basis of type of monomer, the redispersible polymer powder market is segmented into five categories: vinyl acetate redispersible polymer powder, vinyl versatate redispersible polymer powder, ethylene redispersible polymer powder, acrylate redispersible polymer powder, and styrene butadiene redispersible polymer powder. Asia Pacific and North America are the major markets for redispersible polymer powder. Factors such as booming urbanization, rapidly growing construction in both developed and developing countries, and increasing utilization of ready-mixed concrete (RMC) apart from non-hazardous, green, and sustainable construction chemicals in developed countries is driving the demand for redispersible polymer powder in these two regions. On the basis of application area, the global redispersible polymer powder market is segmented into following categories: tiling (adhesives and grouts), flooring, repair, gypsum plaster, waterproofing, ETICS, and plastering. Some leading players operating in the global castor oil and its derivatives market include Wacker Chemie AG, Akzo Nobel, BASF, The Dow Chemical Company, Acquos, Ashland Inc., Puyang Yintai Industrial Trading Company Ltd. Bosson Chemical, and Nordmann Synthomer Ltd.


Tungchaiwattana S.,University of Manchester | Liu R.,University of Manchester | Liu R.,Zhengzhou University of Light Industry | Halacheva S.,University of Manchester | And 3 more authors.
Soft Matter | Year: 2013

Heteroaggregation of dispersions has attracted much interest in the literature, especially when one or more components are stimulus responsive. Here, we study binary mixtures of microgels (MG) and star-like copolymers for the first time. The study investigated the use of complementary hydrogen bonding between carboxylic acid and amide groups to construct heteroaggregates and gels that contained temperature- and pH-responsive components. The pH-responsive MG contained methacrylic-acid and had an apparent pKa of 8.2. Two new star-like copolymers were introduced which comprised a cationic backbone with poly(N-isopropylacrylamide) side-chains. They are abbreviated as M1-PNP. A combination of complementary hydrogen bonding and hydrophobic interactions was shown to cause formation of heteroaggregates for mixed MG/M1-PNP dispersions at room temperature and at pH values less than the MG pKa. MG/M1-PNP heteroaggregate formation occurred over a wide pH-range and also in the presence of 0.2 M NaNO3. The heteroaggregates exhibited temperature-dependent hydrodynamic diameters and zeta potentials. Concentrated MG/M1-PNP dispersions formed self-supporting hybrid gels at 45 °C and gel formation also occurred over a wide pH range. The gels contained 80% MG with respect to total polymer content and were remarkably ductile. They had yield strains greater than or equal to 290%. There was evidence that the elasticity and ductility of the hybrid gels were controlled by the MG and M1-PNP components, respectively. The new M1-PNP star-like copolymers introduced here had superior temperature-triggered gel-formation properties compared to related copolymers and should be a versatile system for conferring temperature-responsive gelation properties to polymer colloids containing carboxylic acid groups. © 2013 The Royal Society of Chemistry.


Pinprayoon O.,University of Manchester | Groves R.,Synthomer Ltd. | Lovell P.A.,University of Manchester | Tungchaiwattana S.,University of Manchester | Saunders B.R.,University of Manchester
Soft Matter | Year: 2011

Although conventional ionomers have been studied for more than 40 years, reports of ionomers prepared using aqueous core-shell nanoparticle dispersions are lacking. In this study we examine the structure and properties of new soft core-shell elastomeric nanoparticles and ionomer films. The nanoparticles consist of a soft poly(Bd) (Bd is 1,3-butadiene) core and a poly(Bd-co-MAA) shell (MAA is methacrylic acid). The nanoparticles were prepared by sequential emulsion polymerisation and were characterised using photon correlation spectroscopy, TEM, PSDA (particle size distribution analysis) and potentiometric titration. Robust ionomer films were formed by casting mixed core-shell nanoparticle/ZnO dispersions at room temperature. The ZnO particles provided aqueous Zn2+ which neutralised the carboxylate groups and imparted ionic crosslinking. The mechanical properties of the films were investigated using DMTA (dynamic mechanical thermal analysis) and stress-strain measurements. Neutralisation substantially increased the film modulus values. This was ascribed to the formation of a poly(Bd-co-MAA)/Zn2+-rich layer that moved inwards from the periphery of the nanoparticles as the degree of neutralisation increased. In contrast to conventional ionomers, the mechanical properties of the present films depend on ionic crosslinking within a honeycomb-type continuous phase that percolates the film. The storage and tensile moduli for the films increased linearly with neutralisation. The films studied here are a new class of nanostructured ionomers and the results obtained should be generally applicable to other films comprising soft-core-shell nanoparticles containing surface carboxylate groups. © 2011 The Royal Society of Chemistry.


Tungchaiwattana S.,University of Manchester | Musa M.S.,University of Manchester | Yan J.,University of Manchester | Lovell P.A.,University of Manchester | And 2 more authors.
Soft Matter | Year: 2014

Ionomers are polymers which contain ionic groups that are covalently bound to the main chain. The presence of a small percentage of ionic groups strongly affects the polymer's mechanical properties. Here, we examine a new family of nanostructured ionomer films prepared from core-shell polymer nanoparticles containing acrylonitrile (AN), 1,3-butadiene (Bd) and methacrylic acid (MAA). Three new AN-containing dispersions were investigated in this study. The core-shell nanoparticles contained a PBd core. The shells contained copolymerised Bd, AN and MAA, i.e., PBd-AN-MAA. Three types of crosslinking were present in these films: covalent crosslinks (from Bd); strong physical crosslinks (involving ionic bonding of RCOO- and Zn2+) and weaker physical crosslinks (from AN). We examined and compared the roles of AN and ionic crosslinking (from added Zn2+) on the structure and mechanical properties of the films. The FTIR spectroscopy data showed evidence for RCOOH-nitrile hydrogen bonding with tetrahedral geometry. DMTA studies showed that AN copolymerised within the PBd-AN-MAA phase uniformly. Tensile stress-strain data showed that inclusion of AN increased elasticity and toughness. Analysis showed that about 33 AN groups were required to provide an elastically-effective chain. However, only 1.5 to 2 ionically bonded RCOO - groups were required to generate an elastically-effective chain. By contrast to ionic bonding, AN inclusion increased the modulus without compromising ductility. Our results show that AN is an attractive, versatile, monomer for increasing the toughness of nanostructured ionomers and this should also be the case for other nanostructured polymer elastomers. This journal is © the Partner Organisations 2014.


Tungchaiwattana S.,University of Manchester | Groves R.,Synthomer Ltd. | Lovell P.A.,University of Manchester | Pinprayoon O.,University of Manchester | Saunders B.R.,University of Manchester
Journal of Materials Chemistry | Year: 2012

Ionomers are polymers containing a low mole fraction of ionic groups bound to the polymer backbone. These ionic groups produce major changes in their structure and mechanical properties. Recently, we introduced a new family of crosslinked poly(Bd)/poly(Bd-co-MAA) core shell nanoparticles (1,3-butadiene and methacrylic acid) that could be ionically crosslinked and cast as nanostructured ionomer films from aqueous dispersions [Pinprayoon et al., Soft Matter, 2011, 7, 247]. The MAA units in the core-shell particles were neutralised by Zn 2+. Here, we explore the structure-property relationships for these new architecturally controlled nanocomposites by investigating 6 new poly(Bd)/poly(Bd-co-MAA) dispersions and films. In this study we varied the extent of covalent crosslinking in the core and the shell at constant ionic crosslinking for the first time. We used dynamic mechanical thermal analysis to establish a general phase map for the new nanostructured ionomers. Stress-strain data show that our nanostructured films have well controlled, and adjustable, modulus and strain at break values. The data show that the core-shell nanoparticle geometry allows the often observed trade-off between elasticity and ductility to be tuned in a manner that is not possible for conventional ionomers. We show that the chain transfer agent (CTA) concentrations used during the preparation of the nanoparticle cores and shells can be used to independently tune the mechanical properties of the films. This is due to variation of the extents of covalent crosslinking. The results of this study should apply to other covalently crosslinked core-shell nanoparticles containing RCOOH groups in the particle shells. © The Royal Society of Chemistry 2012.


The present invention concerns a method of treating a poly(vinyl chloride) composition comprising poly(vinyl chloride) particles and obtained by a process selected from suspension polymerization in an aqueous medium, microsuspension polymerization in an aqueous medium, emulsion polymerization in an aqueous medium and bulk polymerization, which method comprises contacting the poly(vinyl chloride) composition with supercritical carbon dioxide (scCO_(2)), near critical CO_(2) or liquid CO_(2).

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