Preparation of titanium dioxide/poly(methyl methacrylate‐co‐n‐butyl acrylate‐co‐methacrylic acid) hybrid composite particles via emulsion polymerization

Abstract

Titanium dioxide core and polymer shell composite poly(methyl methacrylate-co-n-butyl acrylate-comethacrylic acid) [P(MMA-BA-MAA)] particles were prepared by emulsion copolymerization. The stability of dispersions of TiO 2 particles in aqueous solution was investigated. The addition of an ionic surfactant, sodium lauryl sulfate, which can be absorbed strongly at the TiO 2 /aqueous interface, increases the stability of the TiO 2 dispersion effectively by increasing the absolute value of the potential of the TiO 2 particles. The adsorption of the nonionic surfactant, Triton X-100, on the surface of TiO 2 particles is less than that of the ionic surfactant. Fourier transform IR spectroscopy was used to measure the content of MAA composite particles. Dynamic light scattering characterized the composite particle size and size distribution. The field-emission scanning electron microscopy results for the composite particles showed a regular spherical shape, and no bare TiO 2 was detected on the entire surface of the samples. The composite particles that were produced showed good spectral reflectance compared to bare TiO 2 . Thermogravimetric analysis results indicated the encapsulated TiO 2 and estimated density of composite particles. There was up to 78.9% encapsulated TiO 2 and the density ranged from 1.76 to 1.94 g/cm 3 . The estimated density of the composite particles is suitable at 1.73 g/cm 3 , which is due to density matching with the suspending fluid. The sedimentation experiment indicates that reducing the density mismatch between the composite particles and suspending fluid may enhance the stability.

Nanocomposites of NR/SBR Blend Prepared by Latex Casting Method: Effects of Nano-TiO2 and Polystyrene-Encapsulated Nano-TiO2 on the Cure Characteristics, Physical Properties, and Morphology

“…Figure 3 represents the FT-IR spectra of nTiO 2 , MPTMSnTiO 2 , and PS-nTiO 2 in the range of 4000-400 cm −1 . The peak at 3309 cm −1 shown in the spectrum of nTiO 2 (Figure 3(a)) was contributed to the stretching and bending vibration of the -OH groups on the surface of the nTiO 2 particles, which were active sites for the reaction with methoxy groups of the MPTMS [19,21,23,24], while the broad peak at around 665 cm −1 was assigned to the vibration absorption peak of Ti-O and Ti-O-Ti bonds [19,21,23,24]. By contrast, the additional peaks at 2923, 1726, 1641, 1138, and 1037 cm −1 seen in the spectrum of MPTMS-nTiO 2 (Figure 3(b)) corresponded to the stretching vibration of C-H, C=O, C=C, Si-O, and Ti-OSi bonds, respectively [19][20][21][24][25][26], indicating the binding of methoxy groups in MPTMS to the -OH groups on the nTiO 2 surfaces to introduce double bonds onto the nTiO 2 surfaces, which can further react with the styrene monomer.…”

“…By contrast, the additional peaks at 2923, 1726, 1641, 1138, and 1037 cm −1 seen in the spectrum of MPTMS-nTiO 2 (Figure 3(b)) corresponded to the stretching vibration of C-H, C=O, C=C, Si-O, and Ti-OSi bonds, respectively [19][20][21][24][25][26], indicating the binding of methoxy groups in MPTMS to the -OH groups on the nTiO 2 surfaces to introduce double bonds onto the nTiO 2 surfaces, which can further react with the styrene monomer. For the PS-nTiO 2 (Figure 3(c)), the FT-IR spectrum shows the characteristic peaks of PS at 3024 (C-H arom), 2917 and 2850 (-CH 2 -CH 2 ), 1596 (C=C arom), 1492 and 1448 (-C 6 H 5 ), and 908 and 698 (-CH= arm) cm −1 , while the peaks at 1068 and 543 cm −1 were due to the vibration of Ti-O-Si and Ti-OTi bonds, respectively [19,21,23,24,26,27], indicating the existence of PS on the nTiO 2 particle surface. This confirmed the encapsulation of nTiO 2 particles by PS with the aid of MPTMS coupling agent through the free radical copolymerization of styrene monomers with methacrylate groups of MPTMS that chemically bonded with the nTiO 2 core via in situ differential microemulsion polymerization.…”

“…Nevertheless, each type of filler affects the final properties of nanocomposites in a different way according to their structural and geometrical characteristics. Among the nanofiller precursors, nanosized TiO 2 (nTiO 2 ) has been widely used as a nonblack filler in the rubber industry due to its special properties such as self-cleaning, nontoxicity, photovoltaic effect, antibacteria, UV absorber, high-performance properties, and physicochemical stability [12,[17][18][19][20][21], However, nTiO 2 particles possess a very high specific surface area with a large number of hydroxyl groups (-OH) on their surfaces, which can cause a strong filler-filler interaction and a high tendency for self-agglomeration when they disperse in rubber matrix [2,12,17,[20][21][22][23][24][25][26]. The uneven dispersion of nTiO 2 leads to the unimproved mechanical properties and thermal stability of the rubber nanocomposites.…”

“…For this reason, nanofillers surfaces are commonly modified chemically to reduce their agglomeration by increasing the filler-matrix interaction, while simultaneously decreasing the filler-filler interaction [17,[20][21][22][23][24][25]. Nowadays, encapsulating inorganic nanoparticles by polymer molecules, forming a core-shell structure, has attracted much attention in the nanotechnology according to the change in their surface characteristics and the improved compatibility with polymers in the nanocomposites [6,[19][20][21][22][23][24][25][26][27]. Moreover, the hybrid nanoparticles can be designed to enhance the mechanical properties, thermal stability, and performance of the nanocomposites by combining the advantages of different materials.…”

Morphology and kinetic mechanism of facile one-step preparing TiO2/polyacrylate/TiO2multilayer core–shell hybrid emulsion via miniemulsion polymerization

“…Recently, many different methods have been developed to prepare organic-inorganic hybrid composite particles with core-shell structure, which include the conventional emulsion polymerization, [17][18][19] layer-by-layer (LBL) method, [20,21] miniemulsion polymerization, [22] and so on, [23][24][25][26] The conventional emulsion polymerization is mainly used for radical polymerization in these methods and does not suit well to the encapsulation of preformed polymeric or inorganic materials. The polymerization process of miniemulsion is a highly versatile technique for the formation of a broad range of polymers and structured materials in confined geometries.…”