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91.
92.
Summary: Extensive studies using mussel adhesive protein as a formaldehyde‐free, strong, and water‐resistant adhesive model revealed that a combination of a polymer with catechol moieties and a polymer with amino groups could serve as a strong and water‐resistant wood adhesive. This study demonstrated that the treatment of abundant and readily available brown‐rot‐fungus‐decayed wood with NaBH4 followed by mixing with polyethylenimine resulted in a formaldehyde‐free, strong, and water‐resistant wood adhesive.
93.
94.
Summary: The aim of this study was to evaluate flexural properties of a partially biodegradable glass fibre reinforced composite after water immersion and dehydration. In addition water sorption and solubility was determined. E-glass fibres were preimpregnated with a biodegradable biopolymer of poly(hydroxyproline) amide (PA). The preimpregnated fibres were then further-impregnated with Bis-GMA–TEGDMA-resin and light polymerized (n = 6). There was also specimen made of plain polymer and FRC without PA. After water immersion and/or dehydration, the specimens were tested by the three-point bending test. The flexural strength and Young's modulus was increased in most cases after water immersion and dehydration except for PA containing specimens. The water sorption was <50 µg/mm3 for all studied specimens and solubility was 20 µg/mm3 for specimens without PA and 35 µg/mm3 for specimens with PA. 相似文献
95.
《Journal of polymer science. Part A, Polymer chemistry》2018,56(16):1834-1843
Adhesives obtained by copolymerizing urea, formaldehyde, and difunctional polyetheramine with different molecular weights (230, 600, 900, and 2000 g mol−1) are presented as a more resilient alternative to conventional urea–formaldehyde resins. Urea and polyetheramine contents were varied and the resulting resins characterized by FTIR, 13C‐NMR, and TGA. These resins were used for production of agglomerated cork panels, an application that demands that the binder system is flexible. Polyetheramine with molecular weight 900 g mol−1 yielded the most promising agglomerated cork panel, with remarkable flexibility, good tensile strength, and with the E1 formaldehyde content specification for wood‐based panels used in construction, according to European Standard EN 12460‐5. These new thermoset adhesives have demonstrated to be capable of being used in systems where conventional formaldehyde‐based resins do not perform well due to inherent high rigidity. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1834–1843 相似文献
96.
Liangjiu Bai Lifen Zhang Zhengbiao Zhang Jian Zhu Nianchen Zhou Zhenping Cheng Xiulin Zhu 《Journal of polymer science. Part A, Polymer chemistry》2011,49(18):3970-3979
Three kinds of alumina (acidic, neutral, and basic Al2O3) were effective as additives for the control and rate enhancement of iron‐mediated AGET (activators generated by electron transfer) ATRP (atom transfer radical polymerization) of methyl methacrylate (MMA) in the presence of limited amount of air, using FeCl3·6H2O as the catalyst, tetrabutylammonium bromide or tetra‐n‐butylphosphonium bromide as the ligand, ethyl 2‐bromoisobutyrate as the initiator, and ascorbic acid as the reducing agent. The conversion could be up to 83.9% in the case of basic Al2O3 and 75.3% with neutral Al2O3 only in 13 h, respectively, whereas no polymer could be obtained even in 50 h without additives. The polymers obtained with neutral and basic Al2O3 had controlled molecular weights and low Mw/Mn values (~1.2). Tacticities of the as‐prepared PMMA in the presence of these three kinds of Al2O3 were consistent with that obtained from conventional free‐radical polymerization of MMA. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
97.
Mark Tahtouh John R. Kalman Brian J. Reedy 《Journal of polymer science. Part A, Polymer chemistry》2011,49(1):257-277
Four novel cyanoacrylates, 2‐cyanoethyl 2‐cyanoacrylate, 1‐cyanoethyl 2‐cyanoacrylate, trideuteromethyl 2‐cyanoacrylate and pentadeuteroethyl 2‐cyanoacrylate have been synthesized using a Diels‐Alder protection/deprotection route involving anthracene. The common route for the synthesis of alkyl 2‐cyanoacrylates was found to be unsatisfactory for the production of small quantities of the targeted cyanoacrylates, which have potential as reagents for the mid‐infrared spectral imaging of fingerprints on difficult surfaces. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
98.
《先进技术聚合物》2018,29(1):364-371
This study is aimed at the synthesis of antimicrobial hydroxyapatite (HAP)‐based composites for dental application by stereolithography (SLA). A micron‐sized commercial HAP was modified by methacrylate and quaternary ammonium salt, and, then, it was used in different amounts (namely 2.5, 5, and 10 wt%) as filler for a photocurable custom made resin for SLA. Thermal stability, microstructure, and particles size of the pristine (HAP) and modified HAP (mHAP) were evaluated by thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and particle size analyser (CILAS). The suitability of each formulation for stereolithography process was assessed by measuring viscosity, degree of conversion (DC%) by Fourier transform infrared spectroscopy (FTIR), glass transition temperature, and thermal stability. Photo‐cured specimens for physical, mechanical, and antimicrobial testing were built by SLA. The flexural strength of the samples was measured using a 3‐point bending test method, and the fractured surface was analysed by scanning electron microscopy (SEM). The antimicrobial activity of samples was investigated against some standard microorganisms (Staphylococcus aureus, Escherichia coli, and Candida albicans), as representative Gram positive and Gram negative bacteria and fungus, respectively. The flexural strength increased with a filler content up to 5% and slightly decreased for higher content. SEM analysis confirmed the presence of uniformly distributed HAP. The incorporation of mHAP reduced the bacterial and fungal growth in dose‐dependent manner in comparison with the neat samples. Finally, a prototype of dental bite was built by SLA. 相似文献
99.
Ayse Altin Burcin Akgun Zeynep Sarayli Bilgici Sebnem Begum Turker Duygu Avci 《Journal of polymer science. Part A, Polymer chemistry》2014,52(4):511-522
Three novel dental monomers containing phosphonic acid groups ( 1a and 2a , based on diethyl amino(phenyl)methylphosphonate and 3a based on diethyl 1‐aminoheptylphosphonate) were synthesized in two steps: the reaction of α‐aminophosphonates with acryloyl chloride (for monomers 1a and 3a ) or methacryloyl chloride (for 2a ) to give monomers with phosphonate groups, and the hydrolysis of phosphonate groups by using trimethyl silylbromide. Their (and the intermediates') structures were confirmed by FTIR, 1H, 13C, and 31P NMR spectroscopy. All the monomers dissolve well in water (1<pH<2) and are hydrolytically stable. Their homo‐ and copolymerizations with 2‐hydroxyethyl methacrylate (HEMA) and HEMA/glycerol dimethacrylate were investigated with photo‐DSC. Thermal polymerization of the new monomers in water or in ethanol/water solution was investigated, giving polymers in good yields. X‐ray diffraction results showed only dicalcium phosphate dehydrate formation upon interaction of 1a ‐ 3a with hydroxyapatite indicating its strong decalcification and that monomer‐Ca salts are highly soluble. Some results were also compared to those with a bisphosphonic acid‐containing methacrylamide ( 4a ) previously reported; and the influence of monomer structure on polymerization/adhesive properties is discussed. These properties, especially hydrolytic stability and good rates of polymerization, make these new monomers suitable candidates as components of dental adhesive mixtures. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 511–522 相似文献
100.
Shaohua Chen 《Journal of the mechanics and physics of solids》2006,54(8):1548-1567
A generalized JKR model is established for non-slipping adhesive contact between two dissimilar elastic spheres subjected to a pair of pulling forces and a mismatch strain. We discuss the full elastic solution to the problem as well as the so-called non-oscillatory solution in which tension and shear tractions along the contact interface is decoupled from each other. The model indicates that the mismatch strain has significant effect on the contact area and the pull-off process. Under a finite pulling force, a pair of adhering spheres is predicted to break apart spontaneously at a critical mismatch strain. This study suggests an adhesion mediated deformation sensing mechanism by which cells and molecules can detect mechanical signals in the environment via adhesive interactions. 相似文献