Novel adhesive system based on 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) and hyperbranched polyglycerols

Two hyperbranched polyglycerols bearing 1,1,1-tris(hydroxymethyl)propane or Bisphenol A core and terminal hydroxyl functionality were examined as components of novel wood adhesive systems. Two 1,3-dimethylol-4,5-dihydroxyethyleneurea resins (DMDHEU) were used as crosslinkers. Shear strength tests revealed that the adhesives containing up to 75 wt% of renewable glycerol-derived polyglycerols retained performance comparable to that of neat DMDHEU. The results give way to extending the area of application of hyperbranched polyglycerols in the field of wood adhesives.     

Oligocarbonate diols from ethylene carbonate—Optimization of the synthesis process

Oligocarbonate diols due to their resistance to oxidation and hydrolysis are particularly valuable components of polyurethanes for biomedical applications. It was shown that for their synthesis “green monomer,” ethylene carbonate can be used in the reaction with 1,6‐hexanediol, instead of usually applied toxic and harmful phosgene. Depending on reaction conditions, besides ester exchange leading to the desired product, competitive etherification is often observed. To optimize the reaction conditions leading to oligocarbonates of high molecular weight without oxyethylene fragments, the method of an experimental design was applied. Such approach enabled the estimation of the influence of reaction temperature, ethylene carbonate to 1,6‐hexanediol molar ratio and catalyst (NaCl) concentration on the molar mass of oligocarbonate diol, content of ether bonds and reaction time. Application of central composite method as an experimental design allowed not only to choose the optimal set of conditions, but also the coefficients of the regression equation were interpreted in a chemical way. Oligocarbonate diols obtained under optimal conditions were used for synthesis poly(urethane‐urea)s which exhibited very good mechanical properties (tensile strength 45–50 MPa and elongation at break up to 500%). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Gas phase deposition of aluminum on nickel alloys

A gas phase aluminum deposition process was developed for nickel base alloys. The substrate to be coated is out of contact with a powder mixture which generates the gaseous transport agent. Gas diffusion was shown to be the factor controlling the aluminum deposition rate in the process for both internal and external surfaces. The aluminum deposition rate increased with decreasing partial pressure of the transporting agent. Complex aluminum halides of an alkali or alkaline earth metal were demonstrated to have sufficient “throwing power” to deposit aluminum uniformly on internal surfaces.     

Epoxy resin modified with soybean oil containing cyclic carbonate groups

Carbonated soybean oil (CSO) containing five‐membered cyclic carbonate groups has been obtained in the reaction of epoxidized soybean oil with carbon dioxide in the presence of KI activated by 18‐crown‐6 under 6 MPa CO₂ pressure at 130°C. The CSO was used for modification of bisphenol‐A based epoxy resin. The composition epoxide‐cyclic carbonate was cured using polyamine hardeners by one‐step and two‐step procedures. All cured compositions were characterized for their thermal and mechanical properties and compared with the parent epoxy network. The optimal properties were obtained for compositions containing CSO and cured by one‐step method when phase separation takes place. The mechanical properties were discussed in terms of morphology observed by SEM. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2904‐2914, 2006     

Wood adhesives derived from hyperbranched polyglycerol cross-linked with hexamethoxymethyl melamines

Wood adhesive system based on hyperbranched polyglycerol cross-linked with hexamethoxymethyl melamines was described. The obtained results showed that it was possible to develop polyglycerol-based interior-grade adhesive exhibiting dry shear strengths of the joints exceeding that of the solid wood. Gelling times of the studied formulations were comparable to those of the industrial thermosetting systems (60–80 s at 100 °C). It was also found that wet shear strengths depended on functionality and F/Me molar ratio in the cross-linking resin.     

Optical chloride sensor based on dimer-monomer equilibrium of indium(III) octaethylporphyrin in polymeric film

A novel transduction chemistry for preparing optical anion-selective polymeric films that respond reversibly and selectively to chloride ion activity is demonstrated. The chloride sensors are prepared by casting thin (5-10 microm) plasticized PVC films containing indium(III) octaethylporphyrin hydroxide, along with optimized levels of a lipophilic tetraphenylborate salt, onto glass slides. When bathed in low-pH buffered solutions void of chloride, the porphyrin species spontaneously forms a hydroxide ion-bridged dimer, with the added lipophilic borate species serving as the counteranion for this complex. The maximum for the Soret absorption band of this dimeric species is shifted to 390 nm, from 410 nm for the initial monomeric porphyrin. Increases in chloride ion levels in the bathing solution results in chloride extraction and ligation to the In(III) center, and concomitant breaking of the dimer into monomeric porphyrin species, yielding a decrease in absorbance at 390 nm and an increase in optical signal at 410 nm. Under optimized conditions, optical selectivity coefficients toward chloride over a wide range of other anions (NO3-, ClO4-, SCN-, SO4(2-), F-, Br-, H2PO4-) are measured to be < 10(-3). Of all anions tested, only salicylate yields a slightly greater response than chloride. This selectivity is shown to be adequate for reversible and accurate sensing of chloride levels in diluted serum samples.     

Novel optical material: Polyarylates with heterocyclic side chain groups

Several nonlinear optical polymers containing azometine side‐chain groups have been obtained by interfacial polycondensation. The structures of obtained monomers and polymers were confirmed by infrared, ¹H‐NMR, and ultraviolet spectroscopies. Mechanical, thermal, and optical properties of the obtained polymers were evaluated. The investigations show that some of the new polymers obtained in this study may find use in optical applications. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1017–1028, 1999     

Well, slap my thigh: Expression of surprise facilitates memory of surprising material.

Two studies examined the general prediction that one's emotional expression should facilitate memory for material that matches the expression. The authors focused on specific facial expressions of surprise. In the first study, participants who were mimicking a surprised expression showed better recall for the surprising words and worse recall for neutral words, relative to those who were mimicking a neutral expression. Study 2 replicated the results of Study 1, showing that participants who mimicked a surprised expression recalled more words spoken in a surprising manner compared with those that sounded neutral or sad. Conversely, participants who mimicked sad facial expressions showed greater recall for sad than neutral or surprising words. The results provide evidence of the importance of matching the emotional valence of the recall content to the facial expression of the recaller during the memorization period. (PsycINFO Database Record (c) 2010 APA, all rights reserved)