Search results for "COMPOSITE"
showing 10 items of 4584 documents
Liquid crystal polymers (LCP) as processing aids and reinforcing agents. A study of nylon 6/LCP blends
1989
Influence de petites quantites d'un copolyesteramide thermotropique sur les proprietes mecaniques et la mise en œuvre du polyamide 6
Polymers, Ferroelectric Liquid Crystalline Elastomers
2002
Ferroelectric materials are a subclass of pyro- and piezoelectric materials. They are very rarely found in crystalline organic or polymeric materials because ferroelectric hysteresis requires enough molecular mobility to reorient molecular dipoles in space. So semicrystalline polyvinylidene fluoride (PVDF) is nearly the only known compound. On the contrary, ferroelectric behavior is very often observed in chiral liquid crystalline materials, both low molar mass and polymeric. Ferroelectric LC-elastomers represent an interesting class of material because they combine the ordering of liquid crystalline ferroelectric phases and the rubber elasticity of polymer networks. Switching of the electr…
Enhanced polyurethanes based on different polycarbonatediols
2012
Segmented thermoplastic polyurethanes (PUs) were prepared from 4,4′-diphenylmethane diisocyanate (MDI), 1,4-butanediol (BD) and different macrodiols with a molar mass of 1000. Properties of those PUs based on polycarbonatediol (PCD) were compared with their homologous based on polyesterdiol and polyetherdiol as macrodiols. The proportion used in this study was macrodiol:BD:MDI = 1:2:3, in mole ratio. The hard segment weight percentage is 48 wt% for different PUs. Thermogravimetric analysis, differential scanning calorimetry, differential mechanical analysis, Fourier transform infrared-attenuated total reflection spectroscopy, as well as mechanical properties and retention on flexural prope…
Photocrosslinkable dextran hydrogel films as substrates for osteoblast and endothelial cell growth
2012
Functional hydrogel films on solid supports are versatile materials with large potential for cell growth and tissue engineering. Here, we report on a modular approach to generate functional hydrogel composite films for endothelial and osteoblast cell co-culture. The polymer network of the parent hydrogel was formed by a dextran derivative (BP-CMD), which contained carboxymethyl (CM) groups for further chemical functionalization and benzophenone (BP) moieties as a photocrosslinkable unit. BP-CMD could be synthesized by three different routes, first with the benzophenone unit attached via an amide bond, or second by an ether bond, or third as an ion pair between the benzophenone ammonium salt…
Functionalization of P3HT with Various Mono- and Multidentate Anchor Groups
2018
Due to its favorable optoelectronic properties and the accessibility via Grignard metathesis (GRIM) polymerization, poly(3-hexylthiophene) (P3HT) is one of the most applied conjugated polymers. The ‘living' nature of GRIM polymerization enables the modification of the polymer and the installation of desired properties. In the present study, two versatile approaches for the synthesis of anchor group-modified P3HT have been developed, which enable the functionalization of various inorganic nanoparticles. Depending on the polymerization conditions, mono- and bifunctional ethynyl-terminated P3HT or solely monofunctionalized aldehyde-terminated P3HT was synthesized. Afterwards, the quantitative …
Natural compounds as light stabilizer for a starch-based biodegradable polymer
2014
Abstract The photooxidation behavior of a commercial starch-based biodegradable polymer, i.e., new generation Mater-Bi, loaded with natural stabilizers was investigated in consideration for outdoor agricultural applications. The photooxidation behavior of the biodegradable films was monitored mainly by mechanical tests and spectroscopic analysis. In order to formulate biodegradable films without any synthetic compounds, suitable for outdoor applications and with good photooxidation stability, antioxidants such as α-tocopherol and quercetin (Q) were considered. The results obtained using natural compounds were compared with those obtained by using a synthetic antioxidant and a light stabiliz…
Thermal Analysis, Mechanical and Rheological Behaviour of Melt Manufactured Polyethylene/Liquid Crystal Polymer Blends
2011
Modification of properties of conventional thermoplastics with thermotropic liquid crystal polymers, from one hand, allows decrease their viscosities, substantially facilitating processing conditions, and, from another hand, allows increase their exploitation properties. Orientation of the labile structure of liquid crystal polymer in extrusion or injection moulding causes specific reinforcement (so-called self-reinforcement) to occur in the blends containing liquid crystal polymer. Up to now the effect of self-reinforcement is mostly investigated in the blends, containing considerable amount of liquid crystal polymer. In this research the effect of minor amounts of liquid crystalline co-po…
Polyethylene composites filled with n‐alkyl‐functionalized siloxane‐silsesquioxane resins and sol‐gel silicas
2019
High‐density polyethylene (HDPE) composites filled with silicon‐based fillers were prepared by melt blending. The use of non‐functionalized and n‐octyl‐functionalized siloxane‐silsesquioxane resins and the sol‐gel silicas as fillers allowed us to evaluate the influence of functionalization of the fillers on the properties of the composites. The melting and crystallization temperatures of the composites were found to be only slightly affected by the addition of the silicon‐based fillers. In turn, the crystallization degree values were increased, in particular for the materials containing non‐functionalized fillers. The free‐volume properties of the composites did not change significantly in …
Wood coated with plasma-polymer for water repellence
2008
The effects of cold HMDSO and HMDSO + SF6 plasma treatments on spruce, chestnut and poplar wood were investigated in order to obtain a hydrophobic surface evaluated by microscopic, spectroscopic (FT-IR and LIBS) and contact angle analyses. Cold plasma treatments can increase the surface hydro-repellence without modifying the external aspect and bulk properties of different woods.