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The aim of this research was to prepare composite polymer particles containing bismuth vanadate (BiVO4) particles through microsuspension iodine transfer polymerization ( ms ITP) for fabric coating as a self-cleaning fabric. To reduce the aggregation of pristine BiVO4 particles during the fabric coating process, composite polymer particles containing the visible-light-driven photocatalyst as BiVO4 particles in self-cleaning fabric applications were investigated in the first time. First, BiVO4 particles were prepared via an aqueous chelating method where the stable precursor solutions of Bi3+ and V5+ with ethylenediaminetetraacetic acid ligand were obtained. After calcination at 500 °C, the BiVO4 particles were obtained. To disperse them well in an oil (monomer) phase in ms ITP, the BiVO4 surface was modified by oleic acid as o-BiVO4 to present a hydrophobic surface. The encapsulation efficiency of the o-BiVO4 (≥60%) in composite poly(methylmethacrylate-divinylbenzene) (P[MMA-DVB]/o-BIVO) particles was significantly higher than that (≈10%) of the pristine BiVO4 particles. Using polyethylene glycol 30 dipolyhydroxystearate (DPHS) as a porogen, porous P(MMA-DVB)/o-BiVO4 particles still maintaining their spherical shape were obtained with an 8% particle of DPHS. Furthermore, increasing the hydrophilic polymer shell by adding 2-hydroxyethyl methacrylate (HEMA) in the oil phase of ms ITP, the P(MMA-DVB-HEMA)/o-BiVO4 particles showed a much higher methylene blue (MB) degradation rate under visible light for 1 h (24 mg MB/g BiVO4 or 96% MB degradation) than that (13 mg MB/g BiVO4 or 52% MB degradation) of the pristine BiVO4. Moreover, the fabric coated with porous P(MMA-DVB-HEMA)/o-BiVO4 particles showed a satisfactory self-cleaning property.

Suspension polymerization is widely used for the preparation of microsphere and microcapsules for many applications. However, the formation of secondary particle byproducts decreases drastically th...

The methyl methacrylate (MMA)-based copolymer microcapsules encapsulating Rubitherm®27 (RT27) used as a phase change material were successfully prepared by microsuspension polymerization. The influ...

International audience; Emulsifier-free emulsion iodine transfer polymerization (emulsion ITP) of styrene was carried out using unpurified and purified poly(methacrylic acid)–iodine (PMAA-I). PMAA-I was previously synthesized by solution ITP in dioxane. The solution ITP of methacrylic acid was completed at 40 °C for 24 h. Unexpectedly, 64% of added CHI3 remained in dioxane even after the polymerization. The emulsion ITP was carried out at pH ∼ 9 with unpurified or purified PMAA-I. The number-average diameter (dn) of the polymer particles obtained using purified PMAA-I (148 nm at 93% conversion) was much smaller than that using unpurified PMAA-I (710 nm at 68% conversion). In both cases, in the early stage of the polymerization, polystyrene (PS) particles stabilized by some PMAA-b-PS copolymer chains were formed. This indicates that PMAA-I worked not only as a macro chain transfer agent but also as a colloidal stabilizer. In the unpurified system, the remaining CHI3 also operated as a chain transfer agent. It resulted in PS-I homopolymers having controlled molecular weight in the PS particles. On the other hand, many high molecular weight PS homopolymers were formed in the purified system by emulsion conventional radical polymerization in the PS particles. To depress emulsion conventional radical polymerization, the CHI3 was post-added after 90 min. Nearly uniform submicrometer-sized (82 nm) PS particles with narrow molecular weight distribution (Mw/Mn = 1.24) were achieved. These polymerization behaviors were reasonably explained from the results obtained by gel permeation chromatography and diffusion ordered spectroscopy 1NMR.

The preparation of high performance poly(methyl methacrylate-acrylic acid-divinylbenzene) (P(MMA-AADVB)) microcapsule encapsulating octadecane (OD) having carboxyl groups on the surface for textile application was studied. The P(MMA-methyl acrylate (MA)-DVB) microcapsule was previously prepared by microsuspension iodine transfer polymerization prior to hydrolysis of MA segment to obtain AA in the P(MMA-AA-DVB) shell. Using 30 wt% of MA and 20 wt% of DVB, the latent heats of melting and crystallization of the encapsulated OD were close to those of original OD (245 and 251 J/g-OD, respectively). After hydrolysis, the zeta potential value of the obtained P(MMA-AADVB) microcapsule surface was -33 mV representing the formation of carboxyl groups of PAA derived from PMA. The influences of nucleating agent amount and type on the reduction of supercooling were then investigated. Using 1-octadecanol at 10 wt% of OD provided the best result. Tc of the encapsulated OD increased and reached to that of original OD while the latent heats were maintained. The hydrolyzed P(MMA-AA-DVB) presented higher efficiency than P(MMA-MA-DVB) microcapsules for fabric coating without external binder which may due to the interaction of microcapsule surface functional group with fabric.

The green bacterial cellulose (BC)-based hydrogel materials have successfully prepared by modification and crosslink BC. BC was derived from acetic acid bacteria isolated and selected from ripe fruits. The production of BC was performed by fermentation in various media. It was found that using liquid potato medium represented the highest thickness of BC film (0.80 cm) with 2 wt% solid content covered the media. To reduce the crystallization of BC, carboxyl group was introduced onto BC chains using a carboxymethylation reaction giving carboxymethyl BC (CMBC) and subsequently crosslinked with divinyl sulfone (DVS). The extent of crosslinking influenced on the swelling properties of the hydrogels. Using large DVS amounts (>30 wt%-of CMBC), dense macromolecular network with less capacity spaces in the hydrogel was formed. The maximum water retention value of green hydrogels containing ~3.0 mmol carboxyl groups/g CMBC reached 27 (g/g).

Poly(l-lactic acid) (PLLA) is a well-known biopolymer, usually synthesized via step-growth or ring-opening polymerization from lactic acid or a lactide monomer, respectively. PLLA microspherical particles are produced by dispersion polymerization with a ring-opening lactide monomer using a particular copolymer chain as a stabilizer. This is not easy to achieve when dehydration is needed. Here, a robust and simple synthesis of a nearly monodisperse, submicron PLLA-based particle/capsule was proposed via radical precipitation polymerization without the use of surfactant. A commercial PLLA was first glycolyzed with ethylene glycol to obtain a low molecular weight glycolyzed PLLA (GPLLA). Then, the GPLLA was copolymerized with methacrylic acid and ethylene glycol dimethacrylate monomers using a benzoyl peroxide initiator. Active sites on the GPLLA backbone were generated by hydrogen abstraction of benzoyloxy radicals that further copolymerized before self-assembly to form the polymer particles. Uniform particle size of about 580 nm with a low polydispersity index (PDI) of 0.012 was obtained. This method was also implemented to produce nearly monodisperse capsules containing linalool. The particle size of PLLA-based capsules was about 280 nm with narrow particle size distribution (PDI of 0.120). The PLLA-based capsules effectively inhibited microbial growth of Staphylococcus aureus, Escherichia coli and Candida albicans and were not toxic to human cells.

Although various metal oxide particles have been used as infrared (IR)-reflective materials, the development of cost-effective new materials has still been a challenge for highly efficient IR reflection. In this work, a spinel iron aluminate (FeAl2O4) particle was first proposed as a new candidate IR-reflective material in the form of composite polymer particles prepared by suspension polymerization. High colloidal stable and spherical poly (methyl methacrylate-butyl acrylate-divinyl benzene) (P (MMA-BA-DVB)) particles containing oleic coated-FeAl2O4 particles (P (MMA-BA-DVB)/o-FeAl2O4) with high encapsulation efficiency were obtained. Because of the low Tg PBA component in the polymer particles, the prepared composite polymer particles were easily self-coated onto the substrate without an external binder. The obtained P (MMA-BA-DVB)/o-FeAl2O4 particles at a 40:40:20 ratio of MMA: BA: DVB showed the highest IR reflection, close to that of the pristine FeAl2O4 particles. Moreover, the temperature control efficiency in terms of ΔT of P (MMA-BA-DVB)/o-FeAl2O4-coated glass (15–16 °C) and metal sheets (12–13 °C) was much higher than that of the bare glass and metal sheets (3–4 °C). These results indicate that the prepared composite polymer particles represent excellent IR reflection, temperature control, and self-coating property on various substrates. They would be a good novel candidate for cooling applications.

Emulsifier-free emulsion iodine transfer polymerization (emulsion ITP) of styrene with self-assembly nucleation was successfully carried out with some living features for the first time as follows. Firstly, poly(methacrylic acid) (PMAA; degree of polymerization, 37)-iodide (PMAA37-I) as a macro chain transfer agent was synthesized by solution reversible chain transfer catalyzed polymerization (solution RTCP) with 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile) as an initiator, iodoform as a chain transfer agent and germanium iodide as a catalyst in dioxane at 40 °C. A dioxane solution of PMAA37-I and styrene were added stepwisely under stirring into an aqueous solution (pH∼9), and then emulsion ITP was initiated by adding 4,4′-azobis(4-cyanopentanoic acid) at 60 °C with stirring at 500 rpm. Stable polystyrene emulsion was obtained without coagulation. At 100% conversion, the number-average diameter was 223 nm. Number-average molecular weight (Mn) increased linearly with conversion, which were well closed to theoretical Mn and molecular weight distribution at 100% conversion was comparatively narrow (Mw/Mn∼2.1).

Poly(methyl methacrylate)/Rubitherm®27 (PMMA/RT27) microcapsules were successfully prepared without free PMMA particles as a byproduct by applying microsuspension iodine transfer radical polymerization (ms ITP) of methyl methacrylate/RT27 (=50/50, w/w) droplets containing benzoyl peroxide as initiator and iodoform as control agent dispersed in an aqueous medium for the first time. Both encapsulation efficiencies of RT27 and MMA were ~100%. The obtained microcapsules consisting of RT27 core and PMMA shell were spherical and had a smooth surface. The latent heats (J/g-RT27), which were obtained from experimental data on their latent heats (J/g-capsule) measured with a differential scanning calorimeter and RT27 content (g-RT27/g-capsule) measured with a thermogravimetric analyzer, of melting and solidification of the encapsulated RT27 in the PMMA/RT/27 microcapsule, were almost the same those of pure RT27. Before their measurements, the microcapsule s were treated to remove unpolymerized MMA, free PMMA particles and free (unencapsulated) RT27.

Poly(L-lactic acid) microencapsulated urea was prepared in water-in-oil-in-water (W1/O/W2) system by the solvent evaporation technique. The influence of poly(L-lactic acid) molecular weight on the percent loading, encapsulation efficiency, and the microcapsule morphology was studied using poly(L-lactic acid) having different number average molecular weights (Mn). Using the higher Mn, the smoother shell with complete encapsulation microcapsules was formed. Moreover, the percent loading and encapsulation efficiency of urea also increased with the poly(L-lactic acid) molecular weight. At 80,000 g/mol of poly(L-lactic acid), the obtained microcapsule gave the highest both percent loading (32%) and encapsulation efficiency (56%). The urea control release study of the prepared microcapsules was implemented by in vitro testing. The encapsulated urea was gradually released from the microcapsules, approximately 53, 29, and 22% of poly(L-lactic acid) at 3,000, 30,000, and 80,000 g/mol, respectively, for a m...

Octadecane (OD), a heat storage material, was encapsulated into poly(divinylbenzene-co-methyl methacrylate) or P(DVB-co-MMA) matrix via the microsuspension polymerization. The oil droplets were first generated by using the phase inversion emulsification, i.e., adding a sodium dodecyl sulphate (SDS) aqueous solution into an oil phase (monomers:OD = 1:1) containing various concentrations of poly(vinyl alcohol) (PVA). Results showed that 0.1 wt% of SDS in aqueous medium with the additional rate of 2 mL/min and 3 wt% of PVA in oil phase were the optimal conditions for the formation of nonspherical microcapsules. The smallest number- (dn) and weight- (dw) average diameters of P(DVB-co-MMA)/OD were, respectively, 3.1 and 3.2 µm with a narrow particle size distribution (dw/dn) of 1.02. The latent heats of the encapsulated OD increased with increasing MMA content of microcapsules. The heat of melting (ΔHm; 223 J/g-OD) and crystallization (ΔHc; 230 J/g-OD) of the OD encapsulated in microcapsules using DVB:...

Micrometer-sized poly(methyl methacrylate) (PMMA) particles were successfully prepared without submicrometer-sized by-products for the first time by applying microsuspension iodine transfer polymerization (ms ITP) with benzoyl peroxide as an initiator and iodoform as a chain transfer agent in aqueous dispersed systems. Iodine radicals must react almost immediately after their exit from the monomer droplet, because of their high insolubility in water; we have named this phenomenon the radical exit depression (RED) effect. In contrast, both sub-micrometer and micrometer sized PMMA particles, which are formed based on homogeneous and droplet nucleations, respectively, were obtained by microsuspension conventional radical polymerization (ms CRP). Formation of submicrometer PMMA products as a by-product of ms CRP has been a serious problem for a long time to be overcome in the synthesis of micrometer sized polymers.

The preparation of divinylbenzene (DVB)-methyl methacrylate (MMA) copolymer microcapsule encapsulated Rubitherm27 (RT27) P(DVB-co-MMA)/RT27 used as heat storage material by the microsuspension polymerization was studied to improve the latent heats of the encapsulated RT27 with sufficient polymer shell strength. Percent loading of RT27 and DVB:MMA ratio were optimized. The optimal condition was 30% loading of RT27 and 30:70 (% w/w) of DVB:MMA ratio. The nonspherical microcapsules with a dent having core-shell morphology were obtained. The thermal properties of the encapsulated RT27 in the P(DVB-co-MMA)/RT27 capsules were measured by thermogravimetric analyzer and differential scanning calorimeter. The heats of melting (ΔHm; 153 J/g-RT27) and crystallization (ΔHc; 164 J/g-RT27) of the encapsulated RT27 in the prepared copolymer capsules were higher than those in PDVB and closed to those of bulk RT27 (162 and 168 J/g-RT27 for ΔHm and ΔHc, respectively).

The encapsulation of Rubitherm®27 (RT27), which is one of the most common commercially supplied heat storage materials, by polystyrene (PS), polydivinyl benzene (PDVB) and polymethyl methacrylate (PMMA) was carried out using conventional radical microsuspension polymerization. The products were purified to remove free RT27 and free polymer particles without RT27. In the cases of PS and PDVB microcapsules, the latent heats of melting and crystallization for RT27 ( and , J/g-RT27) were clearly decreased by the encapsulation. On the other hand, those of the PMMA microcapsules were the same as pure RT27. A supercooling phenomenon was observed not only for PS and PDVB but also for the PMMA microcapsules. These results indicate that the thermal properties of the heat storage materials encapsulated depend on the type of polymer shells, i.e., encapsulation by polymer shell changes the thermal properties of RT27. This is quite different from the idea of other groups in the world, in which they discussed the thermal properties based on the ΔHm and ΔHc values expressed in J/g-capsule, assuming that the thermal properties of the heat storage materials are not changed by the encapsulation. Hereafter, this report should raise an alarm concerning the "wrong" common knowledge behind developing the encapsulation technology of heat storage materials.

The microencapsulation of jasmine oil with polymethyl methacrylate (PMMA) was carried out by solvent evaporation method in oil in water (O/W) emulsion system. The oil phase was formed by the mixing of PMMA, jasmine oil and toluene and then dispersed in polyvinyl alcohol solution as stabilizer. After solvent evaporation, PMMA microcapsules with encapsulated jasmine oil were formed. The influence of weight ratio of PMMA:jasmine oil on the preparation of polymer capsule was studied. It was found that using 1:1 weight ratio of PMMA:jasmine oil, the polymer capsules could not prepared. The increase of PMMA content resulting in the formation of spherical PMMA microcapsules as in the case of 2:1 and 3:1 weight ratios. The amount of encapsulated jasmine oil and the encapsulation efficiency was measured with UV-visible spectroscopy. Approximately 72% encapsulation efficiency was obtained.

Poly(l-lactic acid) (PLLA) microencapsulated vitamin E was prepared in oil in water (O/W) emulsion system using solvent evaporation technique. The influence of PLLA:vitamin E weight ratio on the encapsulation was studied. In the case of low molecular weight PLLA, the optimum ratio is 25:1. It was found that using smaller amount of PLLA, microcapsule could not formed. In contrast, vitamin E was well enveloped with lower amount of high molecular weight PLLA, PLLA:vitamin E at 3:1. The obtained capsule was observed with an optical and scanning electron microscopes. The amount of the encapsulated vitamin E was measured with gel permeation chromatograph.

Poly(divinylbenzene) (PDVB) microencapsulated octadecane (OD) (PDVB/OD) used as heat storage material were prepared by suspension polymerization at 70°C using benzoyl peroxide and polyvinyl alcohol as initiator and stabilizer, respectively. The influence of microcapsule size and divinylbenzene (DVB)/OD weight ratio on the microcapsule shape and thermal properties of encapsulated OD were considered. Thermal properties and thermal stability of PDVB/OD microcapsules were determined using differential scanning calorimeter (DSC) and thermogravimetric analyzer. The optical micrographs and scanning electron micrographs showed that the microcapsules have spherical shape only in the case of 50/50 (%w/w) of DVB/OD whereas they were nonspherical with the decreasing of DVB content. However, the core materials were still well encapsulated even increasing the OD content to 70%wt. From DSC analysis, in all cases, the melting temperature of encapsulated OD (28°C) was almost the same as that of bulk OD (30°C), yet it was ...

Composites of natural rubber (NR)/vinyl polymer nanoparticles as polystyrene (PS) and poly(styrene- methacrylic acid) (P(S-MAA)) were prepared by heterocoagulation technique. The polymer nanoparticles were prepared by emulsifier-free emulsion polymerizations at 70°C using potassium persulfate as initiator. Under acidic condition where pos- itive charge was present on the NR latex (NRL) surface, the nanoparticles having negative charge mainly from sulfate group of initiator were able to adsorb on the NRL surface, the electrostatic interaction being the driving force. The scanning electron micrographs showed that the polymer nanoparticles are homogenously distributed throughout NR matrix as nano- clusters with an average size of about 500 and 200 nm for PS and P(S-MAA), respectively. The mechanical properties of NR/PS and NR/P(S-MAA) composite films were compared with the NR host. The nanocomposites, particularly when the polymer nanoparticles are uniformly dispersed, possess significantly enhanced mechanical properties strongly depending on the morphology of the nanocomposites.

In this work, the heterocoaggulation of natural rubber latex (NRL) with polymer nanoparticles having positive charge on their surfaces was studied to prepare polymer nanocomposite. Firstly, poly [styrene-co-2-(methacryloyloxy) ethyl trimethylammonium chrorid (P(S-QDM)) nanoparticles were prepared by emulsifier-free emulsion polymerization at 80 °C for 8 hours using azobisisobutylamide dihydrochloride (AIBA) as initiator. The size (211 nm) of P(S-QDM) particles was measured by dynamic light scattering (DLS). Secondly, the P(S-QDM) emulsion was mixed with NRL at the pH of 9 where the P(S-QDM) and NRL surfaces presented positive (+77.6 mV) and negative (-49.3 mV) charges, respectively. The polymer nanocomposite where P(S-QDM) adsorbed on the NRL surface by electrostatic interaction was characterized with scanning electron microscope, thermogravimetric analyzer and DLS.

In this work, poly (l-lactic acid) (PLLA) microencapsulated urea as fertilizer was prepared in water in oil in water (W/O/W) system. PLLA used as capsule shell was prepared by polycondensation of l-lactic acid with p-toluene sulfonic acid as a catalyst at 140 °C. The prepared PLLA was used to encapsulate urea. Firstly, the aqueous urea solution was dispersed in oil solution of PLLA and chloroform containing polyvinyl alcohol (PVA) as a stabilizer with stirring at 800 rpm. Secondly, the water in oil emulsion was subsequently dispersed in PVA aqueous solution by stirring at 800 rpm to form W/O/W emulsion. Then, it was stirred for approximately 12 hours to evaporate chloroform in the system resulting in the formation of PLLA microencapsulated urea. It was finally centrifuged and dried in vacuum oven. The influence of water and oil phase ratio on the formation of capsule was studied. The obtained capsule was observed with an optical and scanning electron microscopes.

The encapsulation of octadecane (OD) as heat storage material was studied. The core-shell polydivinylbenzene (PDVB)/natural rubber (NR) capsules encapsulating OD was prepared using the Self-assembling of Phase Separated Poly- mer (SaPSeP) method by suspension polymerization. The mixture of dispersed phase consisting of DVB, NR, OD and ben- zoyl peroxide was added in polyvinyl alcohol aqueous solution and then homogenized at 5,000 rpm for 5 minutes. The obtained monomer droplet emulsion was subsequently polymerized at 80°C for 8 hours resulting in PDVB/NR capsule encapsulating OD. The influence of molecular weight and content of NR on the encapsulation efficiency and thermal prop- erties of the encapsulated OD were investigated. It was found that both factors affected on the preparation of PDVB/ NR/OD capsule. High molecular weight NR restricted phase separation of formed PDVB. High NR content also reduced phase separation of PDVB due to the increase of internal viscosity. Then, only the incorporation of appropriate molecular weight and content of NR resulted in the formation of PDVB/NR/OD capsule.

Poly(divinylbenzene) (PDVB) microcapsules containing octadecane (OD) (PDVB/OD) used as heat storage material were synthesized by suspension polymerization at 70 Microencapsulation, Microcapsule, Heat Storage Material, Octadecane, Suspension Polymerization, Poly(Divinylbenzene)C using benzoyl peroxide and polyvinyl alcohol as initiator and stabilizer, respectively. Thermal properties and stability of PDVB/OD microcapsules were determined using differential scanning calorimeter (DSC) and thermogravimetric analyzer. The morphology and structure of microcapsules were characterized by optical microscope, scanning electron microscope and fourier transform infrared spectrophotometer. From DSC analysis, the melting temperature of encapsulated OD (28oC) was almost the same as that of bulk OD (30oC) while it was quite different in the case of the solidification temperature (19oC and 25oC for encapsulated and bulk OD, respectively). The latent heats of melting (184.0 J/g-OD) and solidification (183.2 J/g-OD) of encapsulated OD were reduced from those of bulk OD (241.7 and 247.0 J/g, respectively). However, the prepared PDVB/OD microcapsules are able to be used for heat storage applications.

The thermal properties of n-hexadecane (HD) encapsulated in crosslinked capsule particles containing a water and/or air domain were studied from the viewpoint of heat-storage applications. The capsule particles were prepared by the microsuspension polymerization of divinylbenzene at 70°C with the self-assembling of phase-separated polymer method that we developed. In the differential scanning calorimetric thermograms, pure HD had a single solidification temperature (Ts) peak at 15°C, whereas the encapsulated HD containing a water domain had two peaks at 6 and 1°C. That is, the encapsulated HD containing the water domain required a longer time and lower temperature to complete the solidification than pure HD, which was negative for heat-storage applications. However, once the particles were dried and the water domain was replaced with air, the problem with the partially lowered Ts improved. The air domain was also found in the encapsulated HD core after solidification because of the shrinkage of HD. The presence of the air domain did not affect the thermal stability of the encapsulated HD. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

From the viewpoint of heat storage application, encapsulation of n-hexadecane (HD) was carried out by microsuspension copolymerizations of divinylbenzene (DVB) and acrylic monomers (butyl acrylate, BA; ethyl acrylate, EA) utilizing the self-assembling of phase-separated polymer (SaPSeP) method proposed by the authors. The heat of solidification (H s) of encapsulated HD in the micron-sized, cross-linked particles was determined by the differential scanning calorimeter (DSC). H s of the encapsulated HD in poly(DVB) particles was much lower than that of pure HD, but it was increased with BA or EA content copolymerized up to that of pure HD. Such an influence of encapsulation on the H s was discussed.

The influence of a water domain formed in n-hexadecane (HD) core in cross-linked polymer capsule particles on the thermal properties of encapsulated HD was studied from the view point of heat storage application. The capsule particles were prepared by micro-suspension polymerization of divinylbenzene at 70 °C utilizing the Self-assembling of Phase-Separated Polymer (SaPSeP) method that the authors proposed. The water domain was not observed for particles taken just after the polymerization and kept at 70 °C, but it was gradually formed with an increase of the size during cooling process from 70 °C to room temperature. In differential scanning calorimetric thermograms, pure HD had a single peak because of solidification (Ts) at 15 °C, and the encapsulated HD containing the water domain had two peaks of Ts1 and Ts2, at 6 and 1 °C, respectively. That is, the encapsulated HD containing the water domain required longer time and lower temperature to complete the solidification than the pure HD, which is negative for its application. However, the lower temperature-side peak at Ts2 gradually disappeared with an increase of capsule particle diameter, which seems to be based on the decrease of total interfacial area between the water domains and encapsulated HD in the capsule particles.

Poly(divinylbenzene) (PDVB) microencapsulated octadecane (OD) (PDVB/OD) for use as a heat storage material was prepared by the microsuspension polymerization of DVB/OD droplets, first generated by phase inversion emulsification (PIE). The influence of the surfactant on the colloidal stability, particle size and particle size distribution (PSD) was investigated. Capsules with a size of approximately 1.5 μm, a narrow PSD, and good colloidal stability throughout the polymerization were obtained using polyvinyl alcohol and sodium dodecyl sulfate as the surfactant and cosurfactant, respectively, in the process of PIE. The optical and scanning electron micrographs showed that the microcapsules have a spherical shape and display a dented surface. The thermal properties and thermal stability of the PDVB/OD microcapsules were determined using a differential scanning calorimeter (DSC) and thermogravimetric analyzer, respectively. From the DSC analysis, the onset melting temperature (Tm) of the encapsulated OD (22.6 °C) was slightly lower than that of the bulk OD (28.7 °C), while it was significantly different in the case of the crystallization temperature (Tc, 12.4 °C and 26.3 °C for encapsulated and bulk OD, respectively). The latent heats of melting (Hm, 192 J g−1-OD) and crystallization (Hc, 195 J g−1-OD) of the encapsulated OD were close to those of the bulk OD (215 and 220 J g−1, respectively).

The simple technique as heterocoagulation was used to prepare natural rubber (NR) with poly[styrene-co-2- (methacryloyloxy) ethyl trimethylammonium chloride] (P(S-QDM)) nanocomposites (NR/P(S-QDM)). P(S-QDM) particle was prepared by emulsion polymerization at 80 °C using azobisisobutylamide dihydrochloride as initiator. Under the alkaline condition, NR latex (NRL) surface represents negative charge deriving from protein adsorbed on its surface while strong positive charge of P(S-QDM) surface deriving from QDM structure is obtained. The assembly via electrostatic interaction between NRL and P(S-QDM) particles in the emulsion state is then taken place with pH adjustable from 2 to 8. The particle surface, particle size and charge of the polymer nanocomposites were measured by scanning electron microscope, dynamic light scattering and zeta potential, respectively, to compare those with the original NR properties.