Novel synthesis of nano‐calcium carbonate (CaCO₃)/polystyrene (PS) core–shell nanoparticles by atomized microemulsion technique and its effect on properties of polypropylene (PP) composites

Abstract

Calcium carbonate (CaCO3)/polystyrene (PS) nanoparticles (<100 nm) with core–shell structure were synthesized by atomized microemulsion technique. The polymer chains were anchored onto the surface of nano‐CaCO3 through triethoxyvinyl silane (TEVS) as a coupling agent. Ammonium persulfate (APS), sodium dodecyl sulfate (SDS) and n‐pentanol were used as initiator, surfactant, and cosurfactant, respectively. Polymerization mechanism of core–shell latex particles was discussed. Encapsulation of nano‐CaCO3 by PS was confirmed by using transmission electron microscope (TEM). Grafting percentage of core–shell particles was investigated by Thermogravimetric Analyzer (TGA). Nano‐CaCO3/PS core–shell particles were characterized by Fourier transform infrared (FTIR) spectrophotometer and differential scanning calorimeter (DSC). The results of FTIR revealed existence of a strong interaction at the interface of nano‐CaCO3 particle and PS, which implies that the polymer chains were successfully grafted onto the surface of nano‐CaCO3 particle through the link of the coupling agent. In addition, TGA and DSC results indicated an enhancement of thermal stability of core–shell materials compared with the pure nano‐PS. Nano‐CaCO3/PS particles were blended with polypropylene (PP) matrix on Brabender Plastograph by melt process with different wt% of loading (i.e. 0.1–1 wt%). The interfacial adhesion between nano‐CaCO3 particles and PP matrix was significantly improved when the nano‐CaCO3 particles were grafted with PS, which led to increased thermal, rheological, and mechanical properties of (nano‐CaCO3/PS)/PP composites. Scanning electron microscope (SEM) and atomic force microscope (AFM) images showed a perfect dispersion of the nano‐CaCO3 particles in PP matrix. Copyright © 2011 John Wiley & Sons, Ltd.

Physicomechanical properties of wollastonite (CaSiO3)/styrene butadiene rubber (SBR) nanocomposites

“…To understand the above phenomenon, there are few factors which influence the glass transition temperature ( T g ), (1) the presence of crystalline wollastonite nanorods, (2) the TEVS chemically grafted onto the wollastonite nanorods, (3) compatibility of wollastonite nanorods as filler with SBR matrix, (4) dispersion and aggregation phenomena of wollastonite nanorods into SBR matrix, were taken under consideration. It has been well explained in our earlier work as follows: first, TEVS as coupling agent chemically grafted onto wollastonite nanorods acting as a compatibilizer and brought individual wollastonite nanorods very easily without any agglomeration in between SBR chain segments, and dispersed uniformly. Second, presence of wollastonite nanorods as rigid filler phase, restricts the chain movements and as a consequence T g of the nanocomposites initially increased .…”

“…Thermal stability of the MW/SBR 1–7 nanocomposites was noticeably improved than that of the VZ‐SBR matrix. The data of d on , d off , and W L were shifted to higher side with enhancing the filler content in MW/SBR nanocomposites as compared to VZ‐SBR . The decomposition temperature was increased as much as 33 °C.…”

“…Overall EB is better in case of MW/SBR nanocomposites. The lower EB of BW/SBR nanocomposites is attributed to aggregation of nanorods as well as formation of weaker interfacial region between the unmodified filler surface and matrix resulting in development of cracks . Besides, both nanocomposites showed constant increment in ME 300 (Figure ) and maximum increment was observed at 3 wt % loading of wollastonite nanorods.…”

“…Besides, at higher filler loading (4.5 wt %), BW/SBR nanocomposite [Figure (d)] showed higher agglomeration than MW/SBR nanocomposite [Figure (d)]. The above improvement with modified nano‐wollastonite is due to the hydrophobic nature generated by silane coupling agent on the surface of nano‐wollastonite, enhancing the dispersibility with higher dispersion and less agglomeration …”

In Situ synthesis of poly(styrene-butylacrylate-acrylic acid) latex/barium sulfate nanocomposite and evaluation of their film properties

“…Figure 9 shows the DSC curves of PSBA and its nanocomposite film. The T g values for nanocomposite films filled with 0, 0.5, 1, 1.5, 2, and 2.5% BaSO 4 were measured to be 8,13,17,19,21, and 20 C, respectively. Clearly, the glass transition peak of PSBA in PSBA/ BaSO 4 nanocomposites tends to shift toward a definitely higher temperature as the BaSO 4 nanoparticles loading is increased to 2 wt%.…”