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PMMA Domains (pmma + domain)

Distribution by Scientific Domains
Polymers and Materials Science100%

Selected Abstracts

Porous Polymer Films with Gradient-Refractive-Index Structure for Broadband and Omnidirectional Antireflection Coatings

ADVANCED FUNCTIONAL MATERIALS, Issue 2 2010
Xiao Li
Abstract Porous polymer films that can be employed for broadband and omnidirectional antireflection coatings are successfully shown. These films form a gradient-refractive-index structure and are achieved by spin-coating the solution of a polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA)/PMMA blend onto an octadecyltrichlorosilane (OTS)-modified glass substrate. Thus, a gradient distribution of PMMA domains in the vertical direction of the entire microphase-separated film is obtained. After those PMMA domains are removed, a PS porous structure with an excellent gradient porosity ratio in the vertical direction of the film is formed. Glass substrates coated with such porous polymer film exhibit both broadband and omnidirectional antireflection properties because the refractive index increases gradually from the top to the bottom of the film. An excellent transmittance of >97% for both visible and near-infrared (NIR) light is achieved in these gradient-refractive-index structures. When the incident angle is increased, the total transmittance for three different incident angles is improved dramatically. Meanwhile, the film possesses a color reproduction character in the visible light range. [source]

Nanocellular Foams of PS/PMMA Polymer Blends

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 1 2008
Tetsuo Otsuka
Abstract A nanocellular PS/PMMA polymer blend foam was prepared, where bubble nucleation was localized in the PMMA domains. The blend, which contains dispersed nanoscale PMMA islands, was prepared by polymerizing MMA monomers in a PS matrix to form highly dispersed PMMA domains in the PS matrix by diffusion mixing. The resulting blend was foamed with CO2 at room temperature. A higher depressurization rate at lower foaming temperature made the bubble diameter smaller and the bubble density larger, and a higher PS composition in the blend resulted in a larger bubble density. A void with 40,50 nm in average diameter and a pore density of 8.5,×,1014 cm,3 was obtained as for the finest nanocellular foams. [source]

Morphological and Physical Properties of Triblock Copolymers of Methyl Methacrylate and 2-Ethylhexyl Methacrylate

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 9 2006
Hormoz Eslami
Abstract Summary: Triblock copolymers of methyl methacrylate (MMA) and 2-ethylhexyl methacrylate (EHMA) [that is, poly(MMA,EHMA,MMA)] were prepared by an emulsion atom-transfer radical polymerization. The relationships of their structural, morphological, and physical properties were investigated. The latex particles had core-shell morphologies and the block copolymers experienced phase separation. Small latex particles with a low number of cores could deform and wet silicon-wafer surfaces, but the deformation of large latex particles was restricted by the internal two-phase morphology of the particles. Latex casting produced continuous pinhole-free films, in which hard poly(MMA) (PMMA) cores of different latex particles merged and provided interparticle connections. The morphology of solution-cast films depended on block composition, solvent type, and film thickness. For all the prepared polymer samples, thick films cast in toluene had poly(EHMA) (PEHMA) materials at air surface, whereas those cast in tetrahydrofuran had a sponge-like PMMA surface structure. Thin toluene-cast films from P(MMA,EHMA,MMA) with the block degrees of polymerization () 200,930,200 showed spherical PMMA domains and those from 380,930,380 yielded a protruded worm-like PMMA structure. The copolymer materials were coated on a glass surface for peeling tests. The films gave good hot-melt adhesion properties when the of the PEHMA block was over 600. The peeling strength depended on the lengths of both PEHMA and PMMA blocks. The P(MMA,EHMA,MMA) sample with of 310,930,310 yielded the highest peeling strength of 7.4 kgf,·,inch,1. The developed material is demonstrated to be a good candidate for a solvent-free, hot-melt, pressure-sensitive adhesives for special-purpose applications such as medical tapes and labels. [source]