Hexosamine content of marine biological adhesives

Mytilus edulis byssal threads have been shown to contain both glucosamine and galactosamine. Inadvertent degradation of the material probably is the reason for the reported absence of these hexosamines from the Mytilus adhesive; evidence for this explanation has been found.     

Convenient method for the gas chromatographic analysis of hexosamines in the presence of neutral monosaccharides and uronic acids

A convenient gas chromatographic method has been devised for the analysis of hexosamines in the presence of neutral and acidic sugars, which involves sequential derivatization reactions of nitrous acid deamination, mercaptalation, and trimethylsilylation. This method allows rapid, simultaneous determination of 0.1-1 micromole samples of hexosamines with coefficients of variation of less than 3%.     

Preparation of thermal-enhanced epoxy resin adhesive with organic PCM for applying wood flooring

Epoxy resins are well-known materials that show beneficial properties, such as high tensile strength and modulus, good adhesive properties, low cost, and ease of processing and environmental advantages. However, epoxy resin adhesive has no characteristic of thermal storage. Latent heat storage is one of the favorable kinds of thermal energy storage methods considered for energy saving and thermal efficiency in various fields, such as solar air conditioning systems and buildings. So we prepared thermal-enhanced epoxy resin adhesive by using PCM. This paper addresses the effects of n-hexadecane and sodium lauryl sulfate on the thermal properties and chemical properties of epoxy resin adhesive and HEAC, using differential scanning calorimetry, thermal gravimetric analysis, and Fourier transform-infrared spectroscopy. Also, we evaluated the applicability of composite epoxy resin adhesive to wood-based flooring using n-hexadecane, through measurement of bonding strength from universal testing machine analysis.     

Quantitative gas chromatographic measurement of glycosaminoglycan hexosamines in urine and plasma

A method is described for the quantitative determination of urine and plasma glycosaminoglycans (GAGs) by gas chromatography of the acetylated amino sugars. GAGs were first recovered by precipitation from urine with alkyltrimethylammonium bromide and from plasma by mini-column chromatography after papain digestion. Urine samples (24) analysed for total hexosamines by gas chromatography and for uronic acid by colorimetry had a correlation coefficient of 0.85. The within-run coefficient of variation (C.V.) for nineteen samples from a pooled urine was 5.2% for total hexosamines and that for the ratio of galactosamine to total hexosamines was 3.7%. The corresponding C.V. values for twelve plasma samples from a common pool were 6.5 and 3.7%. The mean ratio of galactosamine to total hexosamine in ten pre-breakfast spot urines was 51.5%. The corresponding ratio in the plasma from twenty adolescent blood donors was 76.3% and the mean total hexosamine content of the GAGs was 47.36 mumol/l.     

Characteristics and Bond Performance of Wood Adhesive Made from Natural Rubber Latex and Alkaline Pretreatment Lignin

The aim of this study was to characterize an aqueous polymer isocyanate (API) type adhesive made from natural rubber latex (NRL) and lignin as base polymers, and to evaluate bond performance of the adhesive as laminated wood adhesive. The base polymers of the adhesive were prepared by blending NRL, polyvinyl alcohol (PVA), and lignin isolated from black liquor of alkaline pretreatment of oil palm empty fruit bunch (OPEFB) and sugarcane bagasse (SB) with compositions of 25/25/0, 25/20/5, 25/15/10, 25/10/15, 25/5/20, and 25/0/25 (w/w/w). The isocyanate crosslinker was added at the level of 15% of the weight of base polymer. The glass transition temperature (Tg), heat degradation, and the homogenity of the adhesive blend were analyzed. The adhesive was used for producing laminated wood (20×8 cm²). Results showed that the addition of lignin in the base polymer blends of API adhesive did not significantly affect the Tg of the adhesives. However, it affected the thermal decomposition and bond performance of the adhesives. There were more residues and less homogenous adhesive solution due to the addition of lignin in the base polyemr blends of API adhesives. The addition of lignin in the base polymer blends caused significant decrease in bond performance of the adhesive applied in glue laminated wood.     

Differential pulse voltammetric study of a typical anaerobic adhesive formulation coated on a glassy carbon electrode

The determination of copper (II) and iron (III) added to an anaerobic adhesive formulation was investigated by differential pulse voltammetry after application of a solution of the adhesive in acetone to a glassy carbon electrode. The best supporting electrolyte was 0.1 M sodium dodecyl sulphate, which ensured adequate surface contact with the adhesive coating. Under optimum conditions, copper (II) (as CuEDTA ^2?) could be determined at levels down to 0.1 mg l^?1 and iron (III) (in some complexed form) down to 2.0 mg l^?1. The method is also capable of detecting the presence of poly (ethylene glycol) dimethacrylate, cumene hydroperoxide and N,N-dimethyl-p-toluidine in a typical formulation.     

In situ wound sprayable double-network hydrogel: Preparation and characterization

In clinical settings the wound-dressing was required easy to use and can match the wound area immediately, at the same time they need to have the properties of hemostats, anti-inflammation and promoting wound healing. To get an ideal wound dressing, we developed a type of gel-like wound adhesive patch from spraying double-network hydrogel, which own the properties of self-antibacterial and can promote wound healing. By spraying, the gel-like wound adhesive patch can match the wound area immediat...     

Controlled release from directly compressible theophylline buccal tablets

The aim of the current study was the development of theophylline buccal adhesive tablets using direct compression. Buccal adhesive formulations were developed using a water soluble resin with various combinations of mucoadhesive polymers. The prepared theophylline tablets were evaluated for tensile strength, swelling capacity and ex vivo mucoadhesion performance. Ex vivo mucoadhesion was assessed using porcine gingival tissue and the peak detachment forces were found to be suitable for a buccal adhesive tablet with a maximum of 1.5 N approximately. The effect of formulation composition on the release pattern was also investigated. Most formulations showed theophylline controlled release profiles depended on the grade and polymer ratio. The release mechanisms were found to fit Peppas’ kinetic model over a period of 5 h. In general the majority of the developed formulations presented suitable adhesion and controlled drug release.     

Hydrolytically stable acidic monomers used in two steps self-etch adhesives

This study deals with the stability of new phosphonic monomers bearing an acrylamide moiety designed to increase the adhesion durability. Synthesis of monomers bearing acrylamide and methacrylate moieties, as well as their use in Self-Etch Adhesives is reported. The adhesion of a degraded methacrylate based adhesive has been evaluated. Homologous self-etching primers containing monomers bearing acrylamide or methacrylate were formulated and used either immediately after formulation or after 18 months. Their adhesive performances were assessed by shear bond strength testing and their degradation measured by NMR, HPLC-MS. While no differences were found in terms of adhesion between fresh and aged acrylamide based adhesive, the instability of methacrylate based ones was demonstrated. Nevertheless, methacrylate based SEAs still have good adhesion abilities. The co-monomer used, N,N′-diethyl-1,3-bis(acrylamido)propane is expected to be responsible for good mechanical properties even for degraded SEAs. Lastly, the stability of acrylamide monomer seems to be of interest in the prospect of developing SEA with longer shelf life.     

A study of the properties of a composite asphalt binder using liquid products of wood fast pyrolysis

The results of a study of the adhesive properties of a composite asphalt binder modified with pyrolytic lignin—a water-insoluble fraction of liquid products of fast pyrolysis of wood—are presented. It is shown that 10 wt % pyrolytic lignin increases the adhesive strength of the composite asphalt binder and the obtained samples of modified asphalt concrete correspond to the requirements of GOST (State Standard) 9128–84.     

A novel corneal adhesive based on functionally coupled PEG-lysozyme hydrogel for wound closure after surgical eye surgery

Corneal wound closure for surgical eye surgeries or accidents is typically performed to prevent pathogens from the sterile intraocular environment and avoid potential postoperative complications. Tissue adhesives are increasingly employed for corneal wound closure with superior treatment efficiency and less adverse effects. In this study, we successfully develop a novel corneal adhesive based on functionally coupled PEG-lysozyme (PEG-LZ) hydrogels for wound closure after surgical eye surgeries. PEG-LZ hydrogels have plenty of micropores and gradually decreased pore size with increasing concentration from 10%, 15% to 20% (w/v), in which PEG-LZ (15%) represents the suitable pH value, gelation time and elastic modulus. PEG-LZ hydrogels have no in vitro cytotoxicity and excellent ex vivo wound closure effectiveness in porcine eyes. The in vivo wound sealant in rabbit eyes by PEG-LZ hydrogels presents a superior therapeutic effect compared with the conventional methods of stromal hydration and suture, in terms of the wound closure percent, mean corneal thickness, percent of wound gaping, and the Descemet membrane detachment. PEG-LZ hydrogels do not induce obvious histological pathology changes. The PEG-LZ corneal adhesive is considered as a tissue adhesive alternative for wound closure after surgical eye surgeries.     

Robust Hydrogel Adhesive with Dual Hydrogen Bond Networks

Hydrogel adhesives are attractive for applications in intelligent soft materials and tissue engineering, but conventional hydrogels usually have poor adhesion. In this study, we designed a strategy to synthesize a novel adhesive with a thin hydrogel adhesive layer integrated on a tough substrate hydrogel. The adhesive layer with positive charges of ammonium groups on the polymer backbones strongly bonds to a wide range of nonporous materials’ surfaces. The substrate layer with a dual hydrogen bond system consists of (i) weak hydrogen bonds between N,N-dimethyl acrylamide (DMAA) and acrylic acid (AAc) units and (ii) strong multiple hydrogen bonds between 2-ureido-4[1H]-pyrimidinone (UPy) units. The dual hydrogen-bond network endowed the hydrogel adhesives with unique mechanical properties, e.g., toughness, highly stretchability, and insensitivity to notches. The hydrogel adhesion to four types of materials like glass, 316L stainless steel, aluminum, Al₂O₃ ceramic, and two biological tissues including pig skin and pig kidney was investigated. The hydrogel bonds strongly to dry solid surfaces and wet tissue, which is promising for biomedical applications.     

Adhesive and electrical properties of the interface between Pb1 − x Mn x Te Crystals and In-Ag-Au alloy

The effect of annealing of Pb_{1 ? x} Mn _x Te crystals at ～690 K and structures on their basis at ～383 K on the adhesive and electric properties of the interface in the Pb_{1 ? x} Mn _x Te-(In-Ag-Au) structure was studied over the temperature range ～77–300 K. The contacts possessed high adhesive strength. The effect of annealing on contact resistance r _c was determined by a change in the specific resistance of crystals, diffusion of Ag atoms into the near-contact area of crystals, and the formation of intermediate phases of the Ag₂Te type at the interface.     

Thermal Resistance of Carborane-Containing Polyurethane-Adhesive Systems

The influence of the structure of polyestercarboranes and a technique of introducing them into the composition of polyurethane–adhesive systems on the physico-mechanical properties and the thermal resistance of glued joints on their basis was studied. It was shown that the introduction of carborane groups into polyurethane adhesive compositions increases their thermal resistance and the level of properties of compositions containing m-carboranes is higher than that in the case of using o-carboranes. The composition of gaseous products released under the thermal decomposition of carborane-containing polyurethane systems in air and in an inert medium is given.     

Advances in glycosaminoglycanomics by 15N-NMR spectroscopy

Recent developments to enhance sensitivity in solution NMR spectroscopy such as the advent and spread of the use of high magnetic fields, cryoprobe technology, isotopic labeling techniques, and new combinations of 2D experiments have pushed the limits in structural NMR analysis of glycosaminoglycans (GAGs). This review is dedicated to the less sensitive ¹⁵N isotope of hexosamines rather than the commonly used anomeric and ring ¹H and ¹³C resonances of uronic acids and hexosamines. Given that GAG types are basically classified on the basis of their composing hexosamine types together with variations of their sulfation patterns, and epimerized forms of the adjacent uronic acids, ¹⁵N-related NMR studies on native GAGs, oligosaccharides, or the various composing amino sugars have proved to be quite useful in the retrieval of both structural and dynamic information, despite the low number of resultant peaks. This in turn reduces significantly chemical shift degeneracy and at the same time facilitates spin and structural assignments. This review covers the principal contributions made so far by solution ¹⁵N-NMR spectroscopy to progress in the structural biology of GAGs in the current glycomics age.

Hot-melt adhesive for shrinkable polyethylene collars

A hot-melt adhesive based on poly(ethylene-co-vinyl acetate) is proposed to for use in the anticorrosion insulation of the butt joints of pipelines with shrinkable polyethylene collars.     

Synthesis and properties of p-aminobenzoic acid triglycidyl ether and polymers based on it

Through the reaction of p-aminobenzoic acid with epichlorohydrin p-aminobenzoic acid triglycidyl ether was synthesized possessing latency and capable of self-curing at an elevated temperature, its structure being confirmed by means of IR spectroscopy, chromatography-mass spectrometry, and chemical analysis. The kinetics of the oligomer curing was examined by differential scanning calorimetry (DSC) and kinetic parameters were found. Based on temperature regimes established by DSC new heat-resistant polymers were synthesized, and their physical, mechanical, thermomechanical, and adhesive properties were determined.     

Adhesive and dielectric properties of novel polyimides with bis(3,3′-aminophenyl)-2,3,5,6-tetrafluoro-4-trifluoromethyl phenyl phosphine oxide (mDA7FPPO)

Polyimides with a low dielectric constant and excellent adhesion were prepared from a diamine containing phosphine oxide and fluorine groups, bis(3,3′-aminophenyl-2,3,5,6-tetrafluoro-4-trifluoromethyl phenyl phosphine oxide (mDA7FPPO), and rigid-rod type dianhydride containing fluorine groups, such as 3,6-di(3′,5′-bis(trifluoromethyl)-phenyl)pyromellitic dianhydride (12FPMDA). The polyimides were synthesized via the known two-step process, preparation of poly(amic-acid) followed by solution imidization, and characterized by FT-IR, NMR, DSC, TGA and TMA. In addition, their solubility, intrinsic viscosity, dielectric constant and adhesive property were also evaluated. For comparison, 3,6-di(4′-trifluoromethylphenyl) pyromellitic dianhydride (6FPMDA) and 3,6-diphenylpyromellitic dianhydride (DPPMDA) were also utilized. The prepared polyimides exhibited high T_g (276-314 °C), excellent thermal stability (>500 °C in air), good adhesive property (104.7-126.3 g/mm), good solubility, and very low dielectric constant (2.34-2.89).     

A model for the examination of phase behaviour in multicomponent systems

The Percus—Yevick equation for a multicomponent system of adhesive spheres is solved exactly. For an m-component system, the phase behaviour is determined by the number and nature of zeros of a system of $\text{m}\text{(}\text{m}\text{+ 1)}\text{2}$ quadratic equations.     

Polaromicrotribometric (PMT) study of the electrochemical formation of polymer films on metallic surfaces: Polyacrolein films

The electrochemical deposition of a polyacrolein film on a metallic surface is optimally carried out in dimethylformamide and 0.1 M benzyltrimethylammonium percholorate. Acrolein can be reduced on Pt, Au, Fe, Ni, Cu and Al, and leads to an adhesive film whose homogeneity depends on the applied reduction potential. The chemical nature of the deposit was determined by elemental analysis and spectroscopy (i.r. and e.s.c.a.). The film formation was followed in situ by means of polaromicrotribometry (PMT) and interpreted as an anionic polymerization process.