Effects of hybridization of lacquer sap with organic silane on drying properties

A hybrid lacquer that dries quickly in low relative humidity was synthesized from liquid kurome lacquer and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AATMS). Hybridization improved the film (mechanical strength and thermal stability) and drying properties of lacquer paints fairly well. The reaction mechanisms between lacquer sap and AATMS were evaluated by various techniques, including NMR spectroscopy, IR spectroscopy, and GPC analysis. The reaction mechanisms were confirmed by the shifts of aromatic proton/carbon signals and the appearance of a methanol peak at the cleavage of the methoxysilyl groups (Si–O–CH₃) and phenolic hydroxyl groups (Ph–OH) of urushiol that were demonstrated by various NMR spectra and IR spectra. Due to these reactions, high molecular weight contents were increased. We considered that the drying properties of the hybrid lacquer were improved by the combination of alcoholysis, the sol–gel reaction, and general curing reaction of lacquer sap.     

Laccase‐catalyzed polymerization drying of Chinese lacquer sap with TiO2 nanoparticles

Nano‐TiO₂/lacquer hybrid coatings are prepared by the blend of nano‐TiO₂ and lacquer sap. Nano‐TiO₂ particles are involved in the laccase‐catalyzed polymerization process of urushiol, which improves the properties of lacquer film. With increasing nano‐TiO₂ from 0 to 5 wt %, the drying time of lacquer film to reach hardened dryness decreases from >12 h to 8 h 30 min under 30 °C and 80% relative humidity. Gel permeation chromatography analysis shows that the addition of nano‐TiO₂ accelerates the polymerization of urushiol. It is also related to the formation of Ti? O? C bonds due to the reaction between nano‐TiO₂ and the radicals produced by laccase‐catalyzed oxidation. The pencil hardness, flexibility, and adhesion of hybrid lacquer film can be improved and reach 4H, 1 mm, and grade 2, respectively. Its inhibition rate against Escherichia coli and Staphylococcus aureus increases from 22.6% and ?21.4% to 49.2% and 67.8%, respectively. Furthermore, nano‐TiO₂ hybrid lacquer films also possess higher thermo‐stability than the raw lacquer film. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45865.     

Interaction between wood and polyurethane‐alkyd lacquer resulting in a decrease in the glass transition temperature

The long‐term properties of paint and glue are of great interest to both manufacturers and users of these materials. If a good bond is achieved, the surface between the wood and the paint or glue will be less susceptible to degradation. Thus, the wood and polymer must be compatible and develop some kind of bonding force between them. A high degree of interaction between wood and commercial polyurethane‐alkyd lacquer was shown as a decrease by 10°C of the glass transition temperature (T_g) for the lacquer on wood compared to the pure lacquer. The lacquer also demonstrated good adhesion to wood at a microscale. The interaction was investigated with dynamic mechanical thermal analysis and scanning electron microscopy fractography. The reason for the decrease in Tg is probably because of the lacquer having a higher free volume when applied to the wood, most likely due to it being subjected to tensile forces developed during the drying of the lacquer. Results from investigations of wood impregnated with two different acrylates, a polymethylmethacrylate and a more hydrophilic acrylate, support the suggestion that a decrease in T_g will occur if the polymer adheres to wood, but that poor interaction with little or no adhesion will result in no decrease in T_g. This article also presents results of the dynamic mechanical behavior of Scots Pine in the tangential direction. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 595–605, 2002     

Effects of aging and moisture on the dynamic viscoelastic properties of oriental lacquer (urushi) film

The effects of aging and moisture on the dynamic viscoelastic properties of three oriental lacquer films were investigated. With aging over 1000 days at room temperature, the glass‐transition temperature of the lacquer films (T_α) shifted to higher temperatures, the maximum loss tangent (tanδ_α) decreased, and the storage modulus at 20°C (E) increased. These changes were analogous irrespective of lacquers. With increasing moisture content, E decreased and tanδ increased at room temperature. Although the equilibrium moisture content of the virgin lacquer (sap) film was higher than that of the clear lacquer film, its E and tanδ were more stable with an increase of moisture content. It was speculated that the polysaccharides aggregated in the sap film did not effectively contribute to the mechanical properties of the film, while their hygroscopicity resulted in higher moisture content. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2288–2294, 2002     

Development of an eco-friendly hybrid lacquer based on kurome lacquer sap

An eco-friendly hybrid lacquer that dries quickly in a low relative humidity environment was synthesized using kurome lacquer (KL) and volatile organic compound-free hydrolyzed amine-functionalized silane (HAS). The HAS structure was characterized by nuclear magnetic resonance (NMR), and the results showed that the ethoxysilyl group in N-(2-aminoethyl)-3-aminopropyltriethoxysilane was completely hydrolyzed. After hybridization with the kurome lacquer, the properties of the hybrid lacquer were measured in detail including viscosity, molecular weight, drying behaviors, and film hardness. Viscosity measurements confirmed the mechanism of hydrolysis and the condensation reaction of silane.     

Development of bio-based hybrid resin,from natural lacquer

Preparation and structure analysis of a bio-based hybrid material composed of natural lacquer, epoxy, and organic silane compounds were investigated using liquid and solid-state nuclear magnetic resonance. The good composition of additives in the hybrid was determined by the drying, hardness, and resin-molding properties. Although natural lacquer alone cannot form thick resins, this bio-based hybrid material showed good resin formation at room temperature without thermal treatment. This result could be based on the enhancement of curing by the sol–gel reaction between natural lacquer and the organic silane compound, and a crosslink reaction between organic silane and epoxy groups. At the same time, oxidative polymerization at the unsaturated side chains in the urushiol was enhanced by the sol–gel reaction because the catechol hydroxyl groups, which have an antioxidative property, reacted with the organic silane. In addition, this bio-based resin possesses a thermoset property because curing of the hybrid was improved by thermal treatment. Based on the structure analyses, the sol–gel reaction between urushiol and organic silane compound proceeded immediately, indicating the high reactivity of this sol–gel reaction. On the other hand, the reaction between bisphenol A-type epoxy resin and the organic silane seems to progress slowly after the epoxy ring opening. In addition, a sol–gel reaction occurred between the amine group in the organic silane and the hydroxyl group formed after the crosslink reaction of the epoxy group. These results suggested that the improvement in drying and molding properties of the hybrid was based on the chemical reactions among all components (i.e., natural lacquer, epoxy, and organic silane).     

Development and characterization of micro-dispersed lacquer

本文利用一种特制的搅拌装置来制备微分散生漆。研究了在不同的搅拌速率和搅拌时间下所获得的生漆微粒子的直径和性能的关系。粒度分布测定表明,经过60分钟且每分钟240转搅拌处理的生漆,其粒子直径分布最窄,平均为0.194微米。凝胶色谱(GPC)分析显示生漆中的寡聚体增加的同时单体的百分含量减少了,意味着在搅拌的过程中发生了聚合反应。另外,微分散生漆的粘度、干燥成膜时间、膜亮度、膜颜色、膜光泽以及耐紫外线等特性也作了深入的探讨。     

Controlled and stereospecific polymerization of rac‐lactide with a single‐site ethyl aluminum and alcohol initiating system

A single‐site ethyl aluminum complex, [2,2‐ diethyl‐1,3‐propylenebis(3,5‐di‐tert‐butyl‐salicylideneiminato)] ethyl aluminum (2), with a geminal diethyl substitutent on the diamino bridge was synthesized by the reaction of AlEt₃ with 1 equiv of N,N′‐(2,2‐diethyl‐1,3‐propylene)bis(3,5‐di‐tert‐butylsalicylideneimine). X‐ray diffraction showed that complex 2 contained a five‐coordinate aluminum atom with a distorted trigonal bipyramidal geometry in the solid state. ¹H‐NMR and ¹³C‐NMR spectra indicated that the two conformational enantiomers of 2 tautomerized quickly on the NMR timescale in solution. In the presence of isopropyl alcohol, the ring‐opening polymerization (ROP) of rac‐lactide with complex 2 produced a crystalline stereoblock polylactide (PLA). The stereoblocks contained an average of 12 units (L? = 12) of enantiomerically pure lactic acid. There was a linear relationship between the monomer conversion and number‐average molecular weights of the polymer. An induction period was observed for the polymerization. The induction period increased with decreasing concentration of catalyst 2 and isopropyl alcohol. In the presence of poly(ethylene glycol) (PEG), a PLA/PEG/PLA stereocomplex was prepared directly by the ROP of rac‐lactide with complex 2, which was confirmed by NMR, gel permeation chromatography, wide‐angle X‐ray diffraction, and differential scanning calorimetry. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 102–108, 2005     

Development of a new type lacquer based on Rhus vernicifera sap with chitosan

A new type lacquer coating was developed by adding certain molecular weight of chitosan to the Rhus vernicifera lacquer sap. The optimum range of chitosan molecular weight and adding quantity were investigated, and the blended lacquer coating was prepared based on these results. The properties, such as molecular weight distribution, particle size distribution, drying times, and gel fraction were examined. In addition, the reaction between urushiol and chitosan is discussed based on the results of nuclear magnetic resonance (NMR) and infrared (IR) measurements. A blended lacquer coating with 3% chitosan dissolve in 5% of citric acid showed almost the same drying time and film hardness as 100% R. vernicifera lacquer sap as examined in an automatic drying time recorder, but had lighter surface color. Furthermore, the UV resistance and viscoelastic property also were investigated in detail.     

Chrome-free corrosion protective coating based on lacquer hybridized with silicate

A lacquer sap hybridized with a silicate oligomer was synthesized, and its characteristics as a chrome-free corrosion protective coating were examined. A new absorption due to a siloxane structure appeared at 6.6 ppm in the NMR and at 1080 and 840 cm⁻¹ in the IR spectra. The hybrid lacquer dries faster due to the reaction between the alkoxy radical of the silicate and hydroxyl of the urushiol, and had a higher glass transition than kurome and raw lacquers. In addition, the ability of the hybrid lacquer to prevent corrosion was comparable to the protection offered by chrome treatment.     

Applied analysis and identification of ancient lacquer based on pyrolysis‐gas chromatography/mass spectrometry

Three lacquer samples taken from a “four‐eared” pottery container, which was designated an important National Cultural Property of Japan excavated in 16–17th century ruins of Kyoto City, were analyzed by pyrolysis‐gas chromatography/mass spectrometry (Py‐GC/MS) and infrared (IR) spectroscopy to determine the source of the lacquer. It is an unexpected result that the lacquer in this pottery container is actually used by Melanorrhoea usitata. Alkylbenzene and alkenylbenzene as cleavage pieces of undecylbenzene (MW = 232 g/mol) and undecenylbenzene (MW = 230 g/mol), which are products of the pyrolysis of thitsiol, were detected in all three samples. Moreover, ω‐phenylalkylcatechols and ω‐phenylalkylphenols, which are the specific components of M. usitata, were also detected by Py‐GC/MS, suggesting that lacquer sap of M. usitata was used by the Japanese people in the 16–17th centuries. In addition, Japanese lacquer culture and the advantages of the Py‐GC/MS method for lacquer analysis are discussed in detail. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Blocked polyisocyanates containing fluorine atoms as crosslinking agents for polyurethane powder coatings

Using alicyclic diisocyanates (HDI, TMDI, IPDI, H₁₂MDI), aliphatic unfluorinated and fluorinated alcohols, dibutyltin dilaurate as well as triethylamine as catalysts, blocked polyisocyanate crosslinkers for powder lacquers were synthesized. The chemical structure of these compounds was characterized by means of IR, ¹H‐NMR, ¹³C‐NMR, and ¹⁹F‐NMR spectroscopy. Their molecular weight distribution parameters were determined by gel permeation chromatography. These blocked polyisocyanates were used for the production of powder lacquer compositions and coatings. The three‐dimensional surface topography and surface chemical structure of the resulting powder lacquers were investigated by means of confocal microscope and ATR FT‐IR. The values of surface roughness parameters were calculated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Characterization of a lacquer film formulated with phosphating reagents for corrosion protection of galvanized substrates

This paper analyzes the chemical composition of the interface resulting from the application of an organic coating (lacquer) containing phosphating reagents on galvanized steel, galvanneal, and galfan substrates and its stability after short periods of exposure to condensing humidity and UV light (UVCON test). X-ray photoelectron spectroscopy (XPS) has shown that the lacquer drying process gives rise to a number of discontinuities on the lacquer surface (pores) exposing the phosphate layer formed on the original metallic coating surface. It is interesting to note the detection of fluoride and nitrite ions and phosphoric acid not combined with zinc (perhaps as HPO₄ ²⁻ and H₂PO₄ ⁻) on the lacquered surfaces before testing, which suggests a tendency of these species to concentrate on the outer surface of the phosphate layer or at the lacquer-phosphate layer interface (in zones covered by the lacquer). After one day of exposure to the UVCON test, XPS reveals the disappearance of the fluoride and nitrite ions and of the free phosphoric acid. After 15 days of exposure to the UVCON test, the carbon content is seen to have decreased considerably, while the zinc, phosphorus, and titanium contents have risen. The low atomic percentages of carbon (only moderately higher than those obtained with the coatings in bare state) and Zn/P atomic ratios close to 1.5 suggest the removal of a very substantial percentage of the lacquer, leaving the zinc phosphate formed on the surface of the different metallic coatings exposed. This quick and significant drop in the lacquer content barely seems to have a repercussion on the degradation of the metallic substrate during the UVCON test, since its visual aspect remains unaltered.     

Urushi (oriental lacquer) — a natural aesthetic durable and future-promising coating

What is oriental lacquer? This article attempts an answer to this question from the viewpoint of materials chemistry and coatings technology of the lacquer in Japan and also describes a strategy for developing oriental lacquers in harmony with the natural environment.     

Influence of an oligomer polyol and monomers on the structure and properties of core–shell polyurethane–poly(n‐butyl acrylate‐co‐styrene) hybrid emulsions

The free‐radical polymerization of alkenyl‐terminated polyurethane dispersions with styrene and n‐butyl acrylate was performed to obtain a series of stable polyurethane–poly(n‐butyl acrylate‐co‐styrene) (PUA) hybrid emulsions. The core–shell structure of the emulsions was observed by transmission electron microscopy, and the microstructure was studied by ¹H‐NMR and Fourier transform infrared spectroscopy. The effects of the poly(propylene glycol)s (number‐average molecular weights = 1000, 1500, and 2000 Da) and the mass ratios of polyurethane to poly(n‐butyl acrylate‐co‐styrene) (PBS; 50/50, 40/60, 30/70, 20/80, and 10/90) on the structure, morphology, and properties of the PUAs were investigated. The average particle size and water absorption values of the PUAs increased with increasing of PBS content. However, the surface tension decreased from 34.61 to 30.29 mN/m. PUA‐2, with a bimodal distribution, showed Newtonian liquid behaviors, and PUA‐3 showed a great thermal stability, fast drying characteristics, and excellent adhesion to packaging films. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43763.     

Novel anion‐exchange organic‐inorganic hybrid membranes prepared through sol‐gel reaction and UV/thermal curing

Anion‐exchange organic‐inorganic hybrid membranes were prepared through sol‐gel reaction and UV/thermal curing of positively charged alkoxysilane and the alkoxysilane containing acrylate or epoxy groups. Properties of prepared hybrid membranes were varied by control of the molar ratio of the precursors. It was shown that the thermal degradation temperatures (T_d) of the membranes were in the range of 212–226°C, water uptakes in the range of 9.6–14.6% and IEC values in the range of 0.9–1.6 mmol g^?1. The hybrid membranes show high permeability to anions, as reflected by the high static transport number (t_?) of the anion (Cl^?). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Curing behaviors of Korean Dendropanax lacquer determined by chemical and physical measures

This work was performed to investigate the curing behaviors of Korean Dendropanax lacquer and to determine its sufficient curing conditions. In FTIR and AFM analyses, the peak area of C?C (1644 cm^?1) and the microadhesion decreased with increasing curing time, attributed to oxidative thermal polymerization (or crosslinking). The magnitude of the microadhesion between the probe and the surface related to the surface tack of the lacquer indicates how well the lacquer was cured and crosslinked. The increased contact angle exhibited increasing lacquer hydrophobicity, due to polymerization, during the curing process. Changes in double bond peak, contact angle, and microadhesion were dependent on the curing temperature. The results obtained by chemical and physical measures showed that Korean Dendropanax lacquer can be effectively (economically) cured at 100°C for 150 min and at 110°C for 120 min. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 625–630, 2004     

Effect of gelatin on the swelling behavior of organic hybrid gels based on N‐isopropylacrylamide and gelatin

Organic hybrid gels based on poly(N‐isopropylacrylamide) and a natural polymer, gelatin, were prepared through two‐step crosslinking with genipin or glutaraldehyde. The effects of the gelatin content on the swelling behaviors and physical properties of these hybrid gels were investigated. The results indicated that the swelling ratio decreased with an increase in the content of gelatin in these hybrid gels. The swelling ratio for the gel crosslinked by genipin was significantly smaller than that for the gel crosslinked by glutaraldehyde. The results also showed that the gel crosslinked with genipin had a higher crosslinking density and a higher gel strength. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1092–1099, 2005     

Drying biodegradable poly(hydroxybutyrate‐co‐3‐hydroxyvalerate) gels in the elongated state to improve their mechanical properties

Polyhydroxyalkanoates are a class of biodegradable polymers that may be used more as environmentally friendly materials if their mechanical properties can be improved. We approached this goal by modifying poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) with a well‐established processing technique involving crosslinking the polymer chains and then drying a swollen gel of the network under uniaxial strain. The mechanical properties of the resulting oriented films were determined in continuous extension as a function of the degree of crosslinking and the extent of strain during the drying process. Crosslinking invariably improved the toughness. Similarly, the subsequent orientation of the process generally increased the toughness as well, but in some cases, a reduction in the extensibility offset the increase in the ultimate stress at break and yielded reduced values of the toughness. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1519–1523, 2005