Acrylate polymer

Résumé

An acrylate polymer (also known as acrylic or polyacrylate) is any of a group of polymers prepared from acrylate monomers. These plastics are noted for their transparency, resistance to breakage, and elasticity. Acrylate polymer is commonly used in cosmetics, such as nail polish, as an adhesive. History The first synthesis of acrylic polymer was reported by G.W.A Kahlbaum in 1880. Acrylic elastomers Acrylic elastomer is a general term for a type of synthetic rubber whose primary component is acrylic acid alkylester (ethyl or butyl ester). Acrylic elastomer possesses characteristics of heat and oil resistance, with the ability to withstand temperatures of 170–180 °C. It is used primarily for producing oil seals and packaging related to automobiles. Acrylic elastomer can generally be characterized as one of two types. "Old" types include ACM (copolymer of acrylic acid ester and 2-chloroethyl vinyl ether) containing chlorine and ANM (copolymer of acrylic acid

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https://en.wikipedia.org/wiki/Acrylate_polymer

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Self-cleaning and wear-resistant polymer nanocomposite surfaces

Feyza Karasu Kiliç, Yves Leterrier, Luca Alois Egon Müller

Superhydrophobic self-cleaning and wear-resistant nanocomposite surfaces were produced by mimicking the hierarchical structure of the lotus leaf using a combination of rapid self-assembly and a UV nano-imprint lithography (UVNIL) process with a silicone master. Two different acrylate formulations containing acrylated silica nanoparticles and an acrylated silicone surfactant were used. The presence of the silicone master did not suppress the spontaneous migration of the surfactant to the polymer surface, which increased its hydrophobic character. Adding acrylated silica particles considerably increased the viscosity of the acrylate suspensions and led to a shear-thinning behavior. However the particles did not prevent the fast migration process of the surfactant and further increased the hydrophobicity of the material, due to increased nanoscale roughness of the nanocomposite surface. The largest increase of hydrophobicity was achieved for the UVNIL printed lotus surfaces using the acrylate formulation with lowest viscosity. These surfaces became superhydrophobic for the highest investigated concentration of silica. These nanocomposite lotus surfaces were, in addition, very hard with a microhardness above 400 MPa and particularly wear-resistant, and were self-cleaning with respect to hydrophobic contamination.

2018

Chargement

Effective encapsulation of small, volatile, weakly water-soluble molecules such as flavors and fragrances is necessary to protect them from degradation, to increase their lifetime, and to improve their water dispersion and fixation depending on the substrate of interest. The aim of this project has been to improve encapsulation and release in order to optimize the performance of fragrance molecules in water-based household (detergents, softeners, etc.) and body care applications (shampoos, lotions, etc.), and fine perfumery applications. More specifically, the aim has been to investigate the effectiveness of "unimolecular micelles" based on amphiphilic multi-arm star-block copolymers with a hyperbranched core with more than 26 functional groups, a hydrophobic inner and a hydrophilic outer shell. These have been prepared from a commercial hyperbranched polyester macroinitiator (HBP) by ring-opening polymerization of ε-caprolactone, followed by the atom transfer radical polymerization (ATRP) of tert-butyl acrylate (tBuA). Hydrolysis of the tert-butyl groups has then been used to convert the poly(tBuA) blocks to poly(acrylic acid) (PAA), resulting in HBP-(PCL)p-(PAA)q pH-dependent amphiphilic star-block copolymers with good control of the molecular weight distribution. These were shown to form stable nanocapsules with a well defined core-shell architecture, as confirmed by thermal and microstructural characterization. The necessity of the core-shell architecture for the effective encapsulation of fragrance molecules in aqueous dispersion has been demonstrated by NMR (nuclear magnetic resonance). The extent of encapsulation reflects the dynamic equilibrium between the free molecules and the fragrance/polymer complex and is dependent on the octanol/water partition coefficient (logP) of the fragrance compounds, as demonstrated with a similar non ionic core-shell architecture HBP-(PBMA)37-(PPEGMA)39 composed of a hydrophobic poly(butyl methacrylate) (PBMA) core and a hydrophilic poly(polyethylene glycol) methyl ether methacrylate (PPEGMA) shell (provided by the Polymer Laboratory of the EPFL). The fragrance loadings in the polymer (HBP-(PCL)p-(PAA)q and HBP-(PBMA)37-(PPEGMA)39), which reached up to 30 wt% depending on the type of the fragrance molecule, were argued to be linked to their solubility in the hydrophobic core of the star-block copolymer. Moreover, under conditions representative of real applications (fine perfumery and softener applications) the star-block copolymers significantly extended the time over which the concentration of certain volatiles remained above the human olfactory threshold. Effective encapsulation and delayed release of small hydrophobic molecules was hence demonstrated to be possible with the present systems. The straightforward synthesis, tailorable chemistry and globular architecture of the star-block copolymers investigated here therefore offer promise for the development of relatively cheap encapsulants with affinities for specific components in fragrance packages, and release triggered by selected substrates according to their surface chemistry.

EPFL2007

Chargement

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Different photocurable acrylates, including two hyperbranched monomers, are compared with an epoxy negative-tone photoresist (SU-8) with respect to their suitability for the fabrication of ultra-thick polymer microstructures in a photolithographic process. To this end, a resolution pattern was used and key parameters, such as the maximum attainable thickness and aspect ratio, the minimum resolution and the processing time were determined. Compared to SU-8, all acrylate materials allowed the fabrication of thicker layers with a fast single layer fabrication procedure. Microstructures with thicknesses of up to 850 μm, an aspect ratio of up to 7.7, a 5.5-fold reduction in internal stress and a 6-fold reduction in processing time compared to SU-8 were demonstrated using an acrylated hyperbranched polyether. The specific development process of the hyperbranched polymer combined with channel design moreover enabled us to produce a high-performance valve for micro-battery devices.

Institute of Physics2008

Chargement

EPFL2007