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Mechanochromic materials have recently received tremendous attention because of their potential applications in humanoid robots, smart windows, strain sensors, anti-counterfeit tags, etc. However, improvements in device design are highly desired for practical implementation in a broader working environment with a high stability. In this article, a novel and robust mechanochromism was designed and fabricated via a facile method. Silica nanoparticles (NPs) that serve as a trigger of color switch were embedded in elastomer to form a bi-layer hybrid film. Upon stretching under ambient conditions, the hybrid film can change color as well as transparency. Furthermore, it demonstrates excellent reversibility and reproducibility and is promising for widespread application.

Hydrogenated acrylic rosin (HAR)/polyacrylate composite emulsions were prepared by seeded semibatch emulsion polymerization method. The effect of HAR amount on monomer conversion rate, coagulum rate, and gel fraction of the composite emulsions as well as the water absorption ratio, adhesion properties, and thermal durability of the HAR/polyacrylate composite latex films was studied; the composites were also characterized by Fourier transform infrared spectroscopy (FT-IR), gel permeation chromatograph (GPC), differential scanning calorimetry, and thermogravimetry. The results showed that with the increase of HAR amount, the monomer conversion rate, gel fraction, molecular weight, and water absorption ratio were all decreased, and the coagulum rate and molecular weight distribution increased. HAR had good compatibility with polyacrylate, and when HAR amount was 4 wt%, the HAR/polyacrylate composite latex film had superior adhesion properties and thermal durability.

The polyacrylate emulsions tackified by polymerized rosin were prepared via seeded semicontinous emulsion polymerization. The effects of polymerized rosin on the monomer conversion, particle size, polymer microstructure (gel fraction, cross-linking density and sol molecular weight) and adhesive properties were studied. The instantaneous conversion, gel fraction, cross-linking density and sol molecular weight decreased significantly due to the chain transfer and inhibition of the abietic acid. Also, the related mechanism was discussed. Dynamic light scattering was used to monitor the particle size of tackified emulsion. The relationship between the main adhesive properties of tackified latex films and polymer microstrcuture was studied.

Organic nano-silica was firstly synthesized by sol-gel method with methyl methacrylate (MMA) and butyl acrylate (BA) in the micelles as dispersing media, tetraethoxysilicate (TEOS) as precursor, hydrochloric acid as catalyst and methacryloylpropyl trimethoxysilane (A174) as modifier. Subsequently, the nano-silica/polyacrylate composite emulsions were directly prepared by in-situ emulsion polymerization under the action of the initiator. The structure and properties were characterized by Fourier transform infrared spectroscopy (FTIR), dynamic light-scattering (DSL), thermogracvimetry (TG) and transmission electron microscopy (TEM). The results showed that A174-modified nano-silica was successfully synthesized in the acrylate-based emulsions by the sol-gel method. The nano-silica was encapsulated by polyacrylate, and the composite latex particles exhibited an apparent core-shell structure. The A174 could improve the lipophilicity of nano-silica and increase the grafting efficiency of polyacrylate on nano-si...

Polyacrylate/polymerized rosin composite emulsions were prepared by seeded semicontinuous emulsion polymerization of acrylate monomers in which polymerized rosin was dissolved. The effects of polymerized rosin content on the polymerization stability, monomer conversion, polymer structure, and adhesive properties were studied. Polyacrylate/polymerized rosin composites were characterized by gel permeation chromatograph (GPC), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogracvimetry (TG). The results showed that with an increase of polymerized rosin content from 0 to 6 wt %, gel fraction and sol molecular weight decreased obviously but monomer conversion was basically unchanged. In contrast, with a further increase of polymerized rosin content, the decreasing rates of gel fraction, and sol molecular weight were slowed down. Meanwhile, monomer conversion decreased remarkably. Moreover, interface failure changed into cohesive failure after the addition of polymerized rosin, and the peel adhesion and shear resistance of composite latex films declined with the increase of polymerized rosin content. Thermal analysis showed that polymerized rosin and polyacrylate were compatible and the composite latex films had good thermal stability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011