Extended control of marine fouling

A process for microencapsulation by complex coacervation, introduced by Green and Schleider in 1957, produced a dry powder form of the liquid biocide tributyltin chloride (TBTCL). Static immersion testing of fiberglass panels painted with the shipbottom paint formulated with 14% w/w TBTCL microcapsules (10–30 μm diam.) gave excellent test results (0% fouling for up to 49 mo) when three coats of this paint were applied to panels. Rationale for the extension of protection against attachment and growth of common marine forms in this formulation are given.     

Chemical discrimination of multilayered paint cross sections for potential forensic applications using time‐of‐flight secondary ion mass spectrometry

Time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) equipped with a bismuth imaging source and an argon gas cluster ion beam (GCIB) was used to image polished cross‐sections of four automotive multilayer paint samples. Secondary ion mass spectrometry chemical imaging of the individual layers was possible after a GCIB sputter ion dose of (7 × 10¹⁵) ions/cm² was applied for the removal of polishing residue, at which point the chemical composition of the individual clear coats could be distinguished using principal components analysis. For the differentiation of the four clear coat chemistries, only four secondary ion peaks were necessary; C₂H₅O⁺ (m/z 45.04), C₉H₉NO₂⁺ (m/z 163.09), and C₁₀H₁₁NO₂⁺ (m/z 177.10) that appeared to be fragments of the carbamate‐based clear coat, and C₇H₁₁⁺ (m/z 95.09) that was strongly associated with the polyurethane‐based clear coat. Clear identification of the four paint samples based on this short peak list highlights the strength of the SIMS technique as a potential forensic approach to discriminate automotive paints and suggests that many more variables could be included in the multivariate and statistical analysis to differentiate a wider range of clear coat chemistries.     

Improved controlled relative humidity dynamic mechanical analysis of artists’ acrylic emulsion paints

After improvements were made to a modified Polymer Labs MkIII DMTA instrument to facilitate repeatable controlled humidity (RH) experiments using isothermal and thermal scanning conditions, the viscoelastic properties of titanium white pigmented artists’ acrylic emulsion films were measured in tensile mode. The effects of temperature, relative humidity and accelerated ageing regimes on two brands of titanium white paints were explored. These paints are highly responsive to changes in temperature and relative humidity, formulation differences affect properties slightly, and while light ageing had a negligible effect, thermal ageing resulted in decreased storage modulus and increased film density.     

Robust and recoverable dual cross-linking networks in pressure-sensitive adhesives

Pressure-sensitive adhesives (PSAs) demand the ability to simultaneously improve toughness and adhesion. However, these requirements of PSAs have remained a great challenge because robust and recoverable characteristics are usually contradictory properties of PSAs. Dual cross-linking networks developed by incorporating dynamic noncovalent bonds into chemical cross-linking networks have the potential to mitigate these requirements in a wide variety of applications including adhesives, hydrogels, and elastomers. Herein, a facile approach to achieve dual cross-linking networks of acrylic PSAs with excellent mechanical properties and high-adhesive performance that integrate physically cross-linked networks into chemically cross-linked networks is proposed. Diurethane acrylic monomer-pentaerythritol ethoxylate (DAM-PEEL) groups were introduced into the acrylic PSA system through photopolymerization. The PSA/DAM-PEEL dual cross-linking networks led to the development of the chemically cross-linked networks for both PSA and DAM via covalent bonds and the physically cross-linked networks between the amide groups of DAM and the hydroxyl groups of PEEL via hydrogen bonds. Consequently, the PSA/DAM-PEEL dual cross-linking networks were able to simultaneously improve the modulus and stretchability. This design strategy for developing dual cross-linking networks of materials could offer potential applications for various adhesive-related applications.     

用激光诱导击穿光谱技术定量分析油漆中的有害重金属

很多轻工业产品需要用到油性油漆,其中的重金属元素的含量是否超标将会直接影响到产品质量及其安全性.因此发展轻工产品中重金属含量的快速检测技术,对促进国民经济的发展和保障消费者生命安全具有重要的意义.我们利用激光诱导击穿光谱技术实现了对油漆中有害重金属含量的快速定性和定量分析.通过观测激光等离子体中重金属原子辐射强度可以定性测量重金属含量的大体水平.然后,在相同检测条件下,将已知浓度的标准样品作为参考,制定出各元素的校正曲线,使用外标法,就能够实现定量分析.对Pb、Cr、Cd三种有害重金属元素,目前检出限分别达到9、3.5和23ppm的水平,分析相对误差小于10%,单次测量时间短于2分钟.汞的结果不太理想,检测灵敏度相对偏低,与其原子辐射寿命较短有关.我们将采取脉冲放电延长汞原子辐射弛豫时间的措施来改进汞元素的分析灵敏度,使其达到较高水平.     

Thermal degradation of butyl acrylate-methyl acrylate-acrylic acid-copolymers

The thermal degradation of copolymers based on butyl acrylate-methyl acrylate-acrylic acid used as acrylic pressure-sensitive adhesives, especially for bonding of plasticizer containing materials, has been investigated using thermogravimetry and pyrolysis-gas chromatography at 250°C. It was observed that during the pyrolysis of butyl acrylate-methyl acrylate-acrylic acid copolymers unsaturated monomers as methyl acrylate, methyl methacrylate, butyl acrylate and butyl methacrylate were formed. During the side-chain butyl acrylate-methyl-acrylate-acrylic acid-copolymer degradation the presence of methyl alcohol and butyl alcohol was observed.     

Synthesis and Evaluation of Adhesion Properties of Homogeneous and Core-Shell Pressure-Sensitive Adhesives

Summary: Pressure-Sensitive Adhesives (PSAs) are used for many applications (e.g. tapes and labels), and the market is still growing as new applications are regularly discovered. Emulsion polymerization is widely used to produce water-based PSAs. In this work, the influence of morphology, diameter and acrylic acid concentration in the particles on adhesion properties (peel, tack and shear) was studied. To do so, two series of homogeneous and core-shell latex particles of poly(butyl acrylate-2-ethyl-hexyl acrylate) with different concentrations of acrylic acid (0, 1, 3 and 5 wt%) and three different average diameters, were synthesized by means of emulsion polymerization techniques. The materials were characterized by dynamic light scattering, zeta potential and transmission electronic microscopy. The contents of acrylic acid in the polymer and dispersed medium were determined and the higher quantity of it was found within the particles. The best equilibrium between adhesion properties was found in the core-shell particles with 3 wt% of AA.     

The effects of short‐term changes in environmental parameters on the release of biocides from antifouling coatings: cuprous oxide and tributyltin

Current and forthcoming UK and European legislation requires environmental risk assessment of antifouling paints. For assessments to be carried out successfully, the leaching rate of biocides from antifouling paints should be determined. Current methods for the measurement of biocide leach rate have been shown to be very susceptible to changes in parameters such as pH, salinity and temperature. Using apparatus designed to simulate environmental conditions the effect of short‐term changes in salinity, pH, temperature, suspended particulate matter and simulated vessel speed on cuprous oxide and tributyltin (TBT) leaching from self‐polishing antifouling paint was investigated. No effect on copper leaching was observed over a wide range of environmentally relevant conditions, whilst vessel speed was the only parameter found to influence TBT release rates significantly. It is suggested that the decrease observed may be due to the formation of a boundary layer which slows down the release of TBT from the paint surface. The environmental authenticity of this observation and its possible implications for the environmental risk assessment of TBT are discussed. Copyright © 1999 Crown Copyright.     

Copolymers of (±)2-ethylhexyl acrylate and 3-[3,3,3-trimethyl-1,1-bis (trimethylsiloxy) disiloxanyl] propyl methacrylate

Statistical copolymers of (±)2-ethylhexyl acrylate and 3-[3,3,3-trimethyl- 1,1-bis (trimethylsiloxy) disiloxanyl] propyl methacrylate were synthesized and the reactivity ratios and the Q and e values were calculated. The glass transition temperatures of the copolymers were in good agreement with the predictions of Fox's equation and Wood's formula. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3571–3574, 1997     

气动力压敏漆发光特性研究

以钌配合物为探针分子,分散于经溶胶凝胶法制备的SiO₂基质中形成对空气压力变化敏感的压敏漆。测定了它们的发光光谱及其氧猝灭性能,定量研究了发光和氧猝灭的关系,并将压敏漆用于风洞模拟试验,在较宽压力变化范围内获得了良好的线性关系。表征对压力变化灵敏度的直线斜率高达0.75.显示出所制备的空气动力压敏漆的性能优异,具有开发应用前景。