蓖麻油基双重交联防腐蚀水性聚氨酯的制备及性能

以异佛尔酮二异氰酸酯（IPDI）、聚碳酸酯二醇-1000(PCDL-1000)、蓖麻油（CO）、季戊四醇三丙烯酸酯（PETA）为主要原料，使用丙酮法制备了一系列双重交联的CO基水性聚氨酯（CWPU）乳液。采用FTIR、紫外-可见分光光度计、铅笔硬度计、电子万能实验机、SEM、电化学工作站对CWPU薄膜进行了表征，测试了CWPU薄膜的拉伸性能、耐水性、耐磨性及耐腐蚀性，探讨了其耐腐蚀机理。结果表明，当CO含量（以乳液溶质总质量计，下同）为4%时，制备的薄膜CWPU的24 h吸水率仅为4.5%，对Q235钢板基底的附着力为0级，对Q235钢板基底的保护效率可达99.05%，表明所制CWPU薄膜具有优异的耐水、防腐蚀性能。     

Polyurethaneurea aqueous dispersions prepared with diethyltoluenediamine as chain extender

A series of polyurethaneurea (PUU) aqueous dispersions either with diethyltoluenediamine (DETDA) or ethylenediamine (EDA) as chain extender were prepared with polyester polyol, isophorone diisocyanate and dimethylol propionic acid (DMPA), and characterized. It was found that the physical properties of the PUU aqueous dispersions prepared with DETDA were similar to or better than those prepared with EDA. Compared with the EDA-extended waterborne PUU films, the water resistance and the mechanical properties of the DETDA-extended waterborne PUU films were enhanced appreciably; these enhancements are attributed to the strong hydrogen bonding in urea carbonyl groups and the ordered structure of hard segments in the systems. The DETDA-extended PUU film with 40 wt.% of hard segment and 4.0 wt.% of DMPA unit showed the lowest water-absorbing amount (2.6 wt.%) over all PUU films studied. The hydrophobic surface of the DETDA-extended PUU film modified with a small amount of aminoethylaminopropyl polydimethylsiloxane (AEAPS) was observed and its hydrophobicity was enhanced by increasing the AEAPS content further.     

Reaction and characterization of crosslinking hyperbranched poly (amine-ester) with succine anhydride

Basing on hydroxyl terminated hyperbranched poly (amine-ester)s (HPAEs), the cross-linking reactions and preparation of ester-crosslinked HPAE films were investigated using succine anhydride (SA) as crosslink reagent. It was proved that the cross-linking reaction between HPAE and SA followed a two-step mechanism. This mechanism provides an efficient route to prepare HPAE/SA cross-linked films, in which, the precursor films were prepared by casting HPAE/SA solution at a lower temperature, and then curing the films at a higher temperature. By varying SA content, the solid HPAE/SA films with different cross-linking degrees were prepared successfully. The highest tensile strength of the cross-linked film could reach 59.60 MPa. With all water contact angle smaller than 74.3°, the crosslinked films demonstrated good hydrophilic properties.     

Polyethylene Grafted Polyether Pentaerythritol Mono-Maleate to Improve Wettability of Liquid on Polyethylene Films

Blends of linear low density polyethylene (LLDPE) and linear low density polyethylene grafted polyether pentaerythritol mono-maleate (LLDPE-g-PPMM) were prepared by melt mixing. The surface of LLDPE/LLDPE-g-PPMM films with different contents of LLDPE-g-PPMM was characterized through contact angle and FT-IR spectroscopy. The tensile properties and light transmission properties of extruded films, as well as the performance of these films compared with commercial anti-fog films, were determined. The carbonyl polar groups on the surface of LLDPE/LLDPE-g-PPMM films increased, and the contact angles of water and glycerol decreased when the content of LLDPE-g-PPMM increased. LLDPE/LLDPE-g-PPMM films showed a noticeable reduction in water drop formation as the LLDPE-g-PPMM content was increased. The transmittancy and haze of LLDPE/LLDPE-g-PPMM films were improved when using increased contents of PPMM, which promotes better wetting of the water on the surface.     

Degradable polyurethane based on star-shaped polyester polyols (trimethylolpropane and ɛ-caprolactone) for marine antifouling

The star-shaped polyester polyols based on initiators (trimethylolpropane or pentaerythritol) and ɛ-caprolactone were prepared by polycondensation reaction. The degradable polyurethane (PU) films were prepared by mixing star-shaped polyester polyols and crosslinker agent (hexamethylene diisocyanate trimer). The hydrolytic degradation and water absorption experiments demonstrated that the PU films could erode in artificial sea water, which were controlled by varying the ratios of ɛ-caprolactone/trimethylolpropane and the arm number of star-shaped polyester polyols. The mechanical properties of PU films and coatings increased with decreasing the ratios of ɛ-caprolactone/trimethylolpropane and increasing the arm number of star-shaped polyester polyols. The surfaces of PU films and coatings kept eroding, which were revealed by scanning electron microscopy. The copper ion release rates from PU coatings reached steady state at about 31 days. The marine field tests of PU coatings demonstrated that the degradable PU coatings based on star-shaped polyester polyols were effective coatings for marine antifouling.     

Effect of citric acid,PVOH, and starch ratio on the properties of cross-linked poly(vinyl alcohol)/starch adhesives

The properties of tapioca starch adhesives were improved by cross-linking and the cross-linked adhesive compared with pure tapioca starch and poly(vinyl alcohol) adhesives. The effect of starch ratio, type of PVOH, and adding citric acid were important factors on the cross-linked adhesives. Wood adhesives made from cross-linked PVOH/starch were prepared by PVOH and tapioca starch, using hexamethoxymethyl melamine (HMMM) and citric acid (CA) as a cross-linking agent and catalyst, respectively. The effect of CA, PVOH/starch ratio, and type of PVOH such as medium (M PVOH) and high molecular weight (H PVOH) were investigated. The condition of the cross-linking reaction was 175?°C for 15?min. The structural properties of cross-linked adhesive were investigated by FT-IR spectroscopy. The results were confirmed in terms of thermal properties with a differential scanning calorimeter (DSC) and the shear strength of the adhesive. The cross-linked adhesive resulted in the increase of T _g and showed good blend compatibility with all of the cross-linked adhesives. The adhesive strength significantly increased when using CA as a catalyst in the cross-linking reaction. The optimum contents of the cross-linked PVOH/starch adhesives were 1:1.8 for M PVOH and 1:0.5 for H PVOH.     

环保型聚氨酯涂料的研究进展

综述了环保型聚氨酯固化剂品种、性能与应用,阐述了水性聚氨酯涂料分类、制备方法和改性研究以及聚氨酯粉末涂料和有机硅聚氨酯功能涂料的改性研究进展。讨论了聚氨酯固化剂中游离单体脱除的工艺和方法,建议采用聚合与高效分离技术相结合的方法降低聚氨酯固化剂中残留游离异氰酸酯单体含量。指出聚氨酯涂料的发展趋势为进一步完善高固体含量羟基树脂的制备技术,发展无异氰酸酯基的潮固化聚氨酯涂料,充分利用可再生的植物油制备无溶剂聚氨酯涂料。     

Reaction and characterization of crosslinking hyperbranched poly(amine-ester) with succine anhydride

Basing on hydroxyl terminated hyperbranched poly(amine-ester)s (HPAEs), the cross-linking reactions and preparation of ester-crosslinked HPAE films were investigated using succine anhydride (SA) as crosslink reagent. It was proved that the cross-linking reaction between HPAE and SA followed a two-step mechanism. This mechanism provides an efficient route to prepare HPAE/SA cross-linked films, in which, the precursor films were prepared by casting HPAE/SA solution at a lower temperature, and then curing the films at a higher temperature. By varying SA content, the solid HPAE/SA films with different cross-linking degrees were prepared successfully. The highest tensile strength of the cross-linked film could reach 59.60 MPa. With all water contact angle smaller than 74.3°, the crosslinked films demonstrated good hydrophilic properties. __________ Translated from Journal of East University of Science and Technology (Natural Science Edition), 2006, 32(10): 1,164–1,168 [译自: 华东理工大学学报 (自然科学版)]     

Preparation and corrosion protective properties of nanostructured titania-containing hybrid sol–gel coatings on AA2024

Titania-containing organic–inorganic hybrid sol–gel films have been developed as an alternative to chromate-based coatings for surface pretreatment of aluminium alloys. Stable hybrid sols were prepared by hydrolysis of 3-glycidoxypropyltrimethoxysilane and different titanium organic compounds in 2-propanol solution in the presence of small amounts of acidified water. Different diketones were used as complexing agents in this synthesis for controllable hydrolysis of titanium organics. The properties of the obtained coatings were compared with those of zirconia-containing films. Electrochemical impedance spectroscopy (EIS) measurements and standard salt spray tests were performed to investigate the corrosion protection performance of the hybrid coatings. It was revealed that their protective properties depend significantly on the nature of metalorganic precursors and complexing agents used in the process of sol preparation. The best anticorrosive protection of AA2024 in chloride solutions is provided by the titania-containing sol–gel films prepared with titanium(IV) tetrapropoxide and acetylacetone as starting materials. In the case of zirconia-containing films, better protective properties were found when applying ethylacetoacetate as a complexing agent.     

Synthesis of polyurethane elastomers hypercross-linked by partially hydrated polyhydroxylated C60

Utilization of polyhydroxylated C₆₀ (fullerenols) in a condensation reaction with diisocyanated oligo(tetramethylene oxide) led to the successful fabrication of elastomeric poly (urethane-ether) networks. These polymer networks exhibit interesting thermal behavior at low temperatures, improved tensile strength and elongation at ambient temperatures, and enhanced thermal mechanical stability at high temperatures, as compared with those of the parent linear polyurethane analogues; or with the conventional oligo (tetramethylene oxide)-derived polyurethane elastomers cross-linked by trihydroxylated reagents (1,I,1-trismethylol propane) or tetrahydroxylated reagents (pentaerythritol). The presence of a limited quantity of water molecules in the condensation reaction of fullerenols with diisocyanated prepolymers modified the physical properties of the resulting elastomeric products with a notable increase in tensile strength, modulus, and Ts over those of elasotmers prepared under anhydrous conditions. These water molecules contributed effectively to the increase of the number of cross-linking centers during the reaction.     

Mechanically strong waterborne poly(urethane-urea) films and nanocomposite films

A series of transparent waterborne poly(urethane-urea) (PUU) films and nanocomposite films were prepared using isocyanate excess (5–50 mol% excess relative to the hydroxyl groups) and omitting the common chain-extension step in the acetone method of the preparation. The surplus isocyanate groups were converted into urea and eventually biuret linkages via the reaction with water during the last phase inversion step. Nanocomposites were prepared by the direct mixing of the PUU nanoparticles in water with aqueous nanosilica or montmorillonite powder followed by slow water evaporation. Variable urea/biuret content is responsible for substantially different tensile properties; the neat organic films show elongation-at-break values of 100%–1120%, tensile strength values of 0.07–22.1 MPa, and energy-to-break of 0.1–85 mJ × mm⁻³. All of the materials can be potentially used as soft-to-hard topcoats, depending on the specific demands. The most promising materials are films prepared at 30 and particularly 40 mol% isocyanate excess.     

Effect of crystalline substances in biodegradable films

Films made of sodium caseinate and gelatine were prepared by casting method from a water solution containing glycerol as a plasticizer to obtain environmentally friendly and fully biodegradable materials for agricultural and packaging applications. Additionally, enzymatic protein cross-linking by microbial transglutaminase was applied. Potassium nitrate (KNO₃) was used as additive to investigate the influence of crystallization on the physical properties of protein films.     

Preparation and characterization of waterborne polyurethaneurea composed of C9-diol-based polyester polyol

A series of polyurethaneurea (PUU) aqueous dispersions were prepared with C9-diol-based polyester polyol (POA) and/or poly(neopentylene adipate) polyol (PNA). The particle size and viscosity of the PUU aqueous dispersions consisting of POA were close to those of a comparable system prepared with PNA, and the high-temperature stability and freeze–thaw stability for all the aqueous dispersions were excellent. The PUU film prepared only with the POA exhibited the lowest water-absorbing amount, the highest tensile strength (51.3 MPa), and the best hydrolytic stability across all PUU films studied. The experimental results also showed a high degree of hydrogen bonding for urea groups and a perfect, ordered structure of hard segments in this kind of PUU film, resulting in excellent water-resistance performance and mechanical properties.     

胺类固化剂对水性环氧钢结构防火涂料性能的影响

以环氧乳液为基料,聚磷酸铵、三聚氰胺、季戊四醇为防火助剂制备了水性膨胀型钢结构防火涂料。研究胺类固化剂的种类和用量对涂料防火性能的影响。结果表明,胺类固化剂的品种对防火涂料防火性能的影响不大,而涂层中的凝胶含量对防火性能有显著的影响。凝胶含量在70%~90%的涂料,燃烧后发泡层的泡孔结构均匀,发泡碳化层强度较高,膨胀倍率较大,因而防火性能较好。     

Dialdehyde Starch Nanocrystals as a Novel Cross-Linker for Biomaterials Able to Interact with Human Serum Proteins

In recent years, new cross-linkers from renewable resources have been sought to replace toxic synthetic compounds of this type. One of the most popular synthetic cross-linking agents used for biomedical applications is glutaraldehyde. However, the unreacted cross-linker can be released from the materials and cause cytotoxic effects. In the present work, dialdehyde starch nanocrystals (NDASs) were obtained from this polysaccharide nanocrystal form as an alternative to commonly used cross-linking agents. Then, 5–15% NDASs were used for chemical cross-linking of native chitosan (CS), gelatin (Gel), and a mixture of these two biopolymers (CS-Gel) via Schiff base reaction. The obtained materials, forming thin films, were characterized by ATR-FTIR, SEM, and XRD analysis. Thermal and mechanical properties were determined by TGA analysis and tensile testing. Moreover, all cross-linked biopolymers were also characterized by hydrophilic character, swelling ability, and protein absorption. The toxicity of obtained materials was tested using the Microtox test. Dialdehyde starch nanocrystals appear as a beneficial plant-derived cross-linking agent that allows obtaining cross-linked biopolymer materials with properties desirable for biomedical applications.     

Flexible,hard, and tough biobased polyurethane thermosets from renewable materials: glycerol and 10-undecenoic acid

The main theme of this work is to develop 100% biobased low viscous polyols from renewable resources. An epoxide compound (UA-GLY-E) was synthesized through esterification of glycerol and 10-undecenoic acid preceded by peroxidation. For the first time, UA-GLY-E was utilized as a building block in the generation of low viscous polyols and polyurethanes therefrom. The biobased polyols were synthesized by epoxide ring opening of UA-GLY-E with different nucleophiles, namely glycerol, water, and methanol. The advantage of these biobased polyols is their low viscosity and at the same time high functionality. These biobased polyols were further converted into poly(urethane–urea) coatings by reacting with methylene diphenyl diisocyanate. The impact of peripheral structural change in the polyols on the properties of polyols and their polyurethane coatings was studied. Flexible, hard, and tough thermosets have been prepared successfully from the same epoxy compound by altering the peripheral moiety in the polyol structure. Biobased polyurethanes prepared from glycerol and water-based polyols have shown better crosslinking density over the methanol-based polyol. Moreover, these biobased polyurethane films have shown good thermal stability, mechanical strength, and chemical resistance as well.     

可再生原料为交联剂制备水性聚氨酯脲

以二苯基甲烷二异氰酸酯(IPDI)、二羟甲基丙酸(DMPA)为硬段,聚氧化丙烯二元醇(GE210)为软段,乙二胺(EDA)为扩链剂,制备了具有良好分散性的阴离子水性聚氨酯脲(PUU)分散液。并用可再生的氧化玉米淀粉对其进行了交联改性。测试结果表明,加入氧化交联淀粉后,水性PUU分散液的表面张力增加,成膜后的力学性能得到改善。同时随氧化淀粉用量的增大,水性PUU膜的拉伸强度也逐渐增大。     

New high performance waterborne organic–inorganic hybrid materials from UV curing

The third generation glycerol based hyperbranched polyester (HBPE-3G) was synthesized by reacting glycerol and 2,2-bis(hydroxymethyl)propionic acid in a stoichiometric molar ratio. This polyester was used as preparation for waterborne hyperbranched UV cured polyurethane–silica hybrid coatings. The acrylic terminated waterborne coatings were prepared by modifying some of the hydroxyl groups HBPE-3G to acidic groups by reacting with maleic anhydride. The remaining hydroxyl groups were reacted with NCO terminated acrylate. Then the prepolymer was neutralized with triethyl amine and dispersed in water. The waterborne hybrid formulations were prepared by mixing 3, 5 and 10% of trimethoxysilylpropyl methacrylate (TMSPM) into the acrylic terminated waterborne coatings. The films were casted and cured under UV light. The various film properties were studied by XRD, AFM, TGA and DMTA instruments. TGA result suggests that the onset degradation temperature and final mass residue increase with increasing TMSPM concentration. DMTA results show that the storage modulus and glass transition temperature increase for the hybrid formulations with increasing TMSPM concentration. The structural characterization of the hybrid coatings was performed using FTIR spectroscopy. The tensile test demonstrated that the mechanical properties improve with the increasing TMSPM content. Surface morphology was studied by atomic force microscopy (AFM). AFM study revealed that TMSPM was crosslinked homogenously through the polymer matrix. The TGA and DMTA data suggest that higher thermal stability and glass transition temperature (T_g) for the TMSPM hybrid films compared to their pure counterparts were obtained with increasing the TMSPM content.     

Investigation of polyurethane (urea)/modified nano-calcium carbonate hybrid aqueous dispersions and their films

This investigation was focused on properties of polyurethane (urea) (PUU) by incorporating silica sol-modified nano-calcium carbonate (CaCO₃). The FT-IR spectroscopy and ζ potential measurement indicated the presence of a hybrid effect due to the hydrogen bonding between the nano particles and the polymer matrix. For these hybrid aqueous dispersions, the particle size decreased as the modified nano-CaCO₃ content increased, and the polydispersity index was very narrow (<1.20). Films prepared with the hybrid PUU aqueous dispersions exhibited excellent waterproof performance: the amount of water absorption was as low as 9.0 wt %, and the contact angle of water on the surface of this kind of film was as high as 93°C. TGA results indicated the high thermal stability of hybrid PUU polymers (223–255°C). The properties like tensile strength, hardness, and elongation at break were influenced by the modified nano-CaCO₃ content in the polymers. The hybrid PUU with 15 wt % modified nano-CaCO₃ content showed the optimum properties. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and properties of a novel UV-curable waterborne hyperbranched polyurethane

A series of ultraviolet (UV)-curable waterborne hyperbranched polyurethane dispersions (WHPUDs) have been successfully synthesized by modifying the hyperbranched polyester H10, which was prepared using pentaerythritol as a core molecule and dimethylolpropionic acid as monomers, with succinic anhydride, toluene diisocyanate (TDI), and hydroxypropyl acrylate (HPA). The H10 was characterized by ¹H nuclear magnetic resonance spectroscopy and matrix-assisted laser desorption/ionization time of flight mass spectrometry. The properties of the WHPUDs with different content of succinic anhydride and TDI–HPA have been investigated by measuring the stability, the particle size, and the rheological behavior. The effects of the content of succinic anhydride and TDI–HPA were studied in terms of UV-curing rate, water resistance, and thermogravimetric behaviors of WHPUD coatings. The WHPUDs showed good appearance, particle size, viscosity, and storage stability. The WHPUD films showed superior photosensitivity and the percent conversion of C=C bonds reached about 80% when the radiation time was 50 s. Moreover, the UV-cured films had good water resistance and thermostability, which can benefit a waterborne polyurethane resin for waterborne coatings.