Antifouling activity of novel polyisoprene-based coatings made from photocurable natural rubber derived oligomers

Natural rubber is a renewable resource with a potential as precursor of a very wide range of novel polymers, including polyisoprene-based surfaces with antifouling (AF) activity. In this work, new ionic and non-ionic coatings were prepared by the photocrosslinking reaction of photosensitive cis-1,4-oligoisoprenes, bearing a variable number of ammonium groups. The photochemical crosslinking was achieved using radical (via acrylate groups) or cationic (via epoxy groups) processes. Surface properties of these coatings were studied by static contact angle measurements and AFM imaging. Assessment of bioactivity demonstrated that most of the resulting coatings showed AF potential against fouling organisms: growth inhibition of marine bacteria (Pseudoalteromonas elyakovii, Shewanella putrefaciens, Cobetia marina, Polaribacter irgensii, Vibrio aestuarianus) and fungi (Halosphaeriopsis mediosetigera, Asteromyces cruciatus, Lulworthia uniseptata, Zalerion sp., Monodictys pelagica); decreased adhesion of microalgae (Navicula jeffreyi, Cylindrotheca closterium, Chlorarachnion globosum, Pleurochrysis roscoffensis, Exanthemachrysis gayraliae, Amphora coffeaeformis); inhibition of attachment and/or germination of spores of Ulva intestinalis. The best AF activity was obtained with the ionic surfaces. These new coatings prepared from precursors obtained from natural rubber are in essence active by contact. As the biocidal functions are fixed covalently to the polymer chain, detectable release of biocidal products in the marine ecosystem is prevented so that a valuable environment-friendly alternative for new AF coatings is hereby proposed.     

Antifouling effect of hydrogen peroxide release from enzymatic marine coatings: Exposure testing under equatorial and Mediterranean conditions

Hydrogen peroxide (H₂O₂) may be considered an environmentally friendly antifouling alternative to common biocides such as Cu₂O and various organic compounds. In this work, the efficiency of antifouling coatings releasing hydrogen peroxide via enzyme-mediated conversion of starch, under Mediterranean and equatorial climatic conditions, is investigated. During seawater exposure of the coatings, starch is first converted to glucose by glucoamylase (rate-controlling step) and subsequently glucose is rapidly oxidised by hexose oxidase in a reaction producing hydrogen peroxide.     

Preparation of nanometer dispersed polypropylene/polystyrene interpenetrating network using supercritical CO2 as a swelling agent

Nanometer dispersed polypropylene/polystyrene (PP/PS) interpenetrating networks (IPNs) have been prepared by the radical polymerization and crosslinking of styrene (St) within supercritical (SC) CO₂-swollen PP substrates. In this method, monomer St, crosslinking agent divinyl benzene (DVB), and the initiator benzoyl peroxide were first impregnated into PP matrix using SC CO₂ as a solvent and swelling agent at 35.0 °C, and then the polymerization and crosslinking were carried out at 120 °C. The composition of the IPNs can be controlled by SC CO₂ pressure, concentrations of St and DVB in the fluid phase. Transmission electron microscopy shows that the PS is homogeneously dispersed in the IPNs and its phase size is in the range of 20-30 nm. The impact strength, tensile strength, and elongation-at-break of the PP/PS IPNs increase with increasing PS percentage in the IPNs.     

Novel coatings from renewable resources for the protection of bronzes

End-capped poly(lactic acid)s with a benzotriazole moiety were synthesized by Ring Opening Polymerization of lactide, characterized by spectroscopic methods and tested as protective coatings on selected bronze surfaces. Performances of functionalized polymers were evaluated in terms of colour changes of the treated metal and stability of the coating. A comparison between end-capped polymers and a mixture of poly(lactic acid) and benzotriazole was also run. End-capped poly(lactic acid)s showed excellent stability to photochemical and thermo-hygrometric ageing and better performances than a blend of poly(lactic acid) and benzotriazole. These polymers show promising performances for metal's coating.     

Polymeric blend microspheres for controlled release of theophylline

Microspheres of poly(vinyl alcohol) (PVA) and hydroxyethyl cellulose (HEC) were prepared as semi‐interpenetrating networks (IPNs), crosslinked with glutaraldehyde and used in controlled release of theophylline (THP), an anti‐asthmatic drug. Formulations were characterized by X‐ray diffraction (XRD) to understand uniform distribution of THP, Fourier transform infrared (FTIR) spectroscopy to understand chemical interactions, universal testing machine (UTM) for mechanical stability, and scanning electron microscopy (SEM) for investigating the morphology of the microspheres produced. SEM indicated smooth surfaces of the microparticles and sizes of around 10–15 μm giving high encapsulation efficiency up to 69%. Equilibrium uptake performed in double distilled water and in vitro release studies performed in 1.2 and 7.4 pH buffer media indicated the effect of extent of crosslinking and HEC content of the semi‐IPN matrix on the release of THP that was extended up to 12 h. Analysis of in vitro results using empirical equation suggested a deviation from the Fickian transport. Drug diffusion was estimated from the Fick's diffusion equation for spherical geometry. Kinetics of drug release followed the Higuchi square root equation, indicating that release is diffusion‐controlled. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

机械加工脱模剂废水处理工程实例

从废水水质特性、处理工艺分析、设计参数、处理效果及运行成本等方面,介绍了江苏某机械加工厂的废水处理工程。工程实践表明,采用隔油—混凝气浮—混凝沉淀—UASB—生物接触氧化—砂滤组合工艺可有效处理脱模剂废水,工程调试运行后,COD、SS、石油类的去除率都达到90%以上,最终出水水质稳定且均达到《污水综合排放标准》(GB 8978—1996)三级标准要求。     

京尼平交联大豆蛋白/壳聚糖复合凝胶的控释

利用天然无毒的京尼平交联大豆蛋白(SB)和壳聚糖(CS)制备复合水凝胶(HD)并用作茶碱的控释载体。同时对其在模拟胃肠液和pH7.4缓冲液（PBS）中的控释特性进行了研究。结合扫描电镜和红外光谱以及核磁共振表征了复合凝胶的表观形态和结构。结果表明,复合水凝胶中大豆蛋白和壳聚糖通过京尼平发生了明显的交联作用,并呈现致密的片层结构。复合凝胶在模拟胃肠液和pH7.4PBS中均呈现溶胀现象,在模拟胃液中的溶胀度较低。而且凝胶在pH1.2模拟胃液中的释放量比模拟肠液和pH7.4PBS液中的低,并发现该凝胶具有pH响应,在120 h内可实现对茶碱的可控释放。因此,这种京尼平交联的复合凝胶具有作为药物在胃肠道中定向运送载体的潜力。     

Development of mesoporous bioactive glass-containing macroporous titanium for controlled release of antimicrobial drugs

Biofilm-associated infections pose a serious threat to the long-term survival of metal-based bone implants, which can potentially be resolved by the controlled delivery of antimicrobial agents locally at the implant surface. Mesoporous bioactive glasses (BAGs) are multifunctional materials able to combine bone-bonding properties with such a drug release functionality. Here, we propose for the first time to modify a macroporous Ti implant material with an antimicrobial-releasing BAG phase. The feasibility of a sol-gel synthesis route, including the structure-directing agent (SDA) Pluronic F127, and its effect on the mesoporous structure and concomitant drug release performance was evaluated. Mesopore sizes ranged from 3.4 nm for SDA-free to 3.7 nm for SDA-derived BAG, thereby both enabling configurational diffusion of the antiseptic chlorhexidine (CHX), but the latter showed a more narrow pore size distribution leading to a slower, more controlled release. Adjusting the feed concentration allowed fine-tuning the daily CHX release through the SDA-derived Ti/BAG composite to 1.4 μM. Even though just below the biofilm inhibitory concentration, this daily release rate was sufficient to effectively prevent Streptococcus mutans biofilm formation on the surface of the material. This proof-of-concept for a temporary antimicrobial-releasing bioceramic surface modification on Ti can be of interest for orthopedic implants.     

Electroactive polyacrylamide/chitosan/polypyrrole hydrogel for captopril release controlled by electricity

The demand for the development of new therapies and devices for controlled drug release has been continuously increasing, especially those based on materials sensitives to external stimuli, such as electricity. Therefore, in this work, acrylamide was polymerized in the presence of chitosan (CS), using N,N′-methylenebisacrylamide as cross-linking, followed by immersion in pyrrole aqueous solution and chemical polymerization to obtain an electroactive hydrogel of polyacrylamide/CS/polypyrrole (PA/CS/PPy) (67.5/7.5/25% wt.); this electroactive hydrogel was later used in drug delivery controlled by electricity studies. The synthesized PA/CS/PPy hydrogel was characterized by scanning electron microscopy, FTIR spectroscopy, and thermogravimetric analysis. It was observed that the hydrogel presented pores in the range of 50–200 μm with CS and PPy well incorporated to the cross-linked PA. The hydrogel swelling percentage (S) was determined at different pHs. It was observed that S was independent of pH, with S = 700% and a swelling kinetics described by the Fickian diffusion mechanism at alkaline pH. PA/CS/PPy hydrogel was used to absorb captopril (a drug for hypertension control), and its kinetics release at different applied potentials and pH was studied. Release kinetics were described by the Korsmeyer–Peppas model, while release mechanism was a Case-II transport without current at alkaline pH; under electrical stimuli, the mechanism presented an anomalous transport with ON–OFF profile, increasing the release rate with the applied voltage showing its electroactivity in the captopril release.     

种衣剂用AMPS/VAc/BA三元共聚成膜剂的合成

采用乳液共聚法,以2-丙烯酰胺-2-甲基丙磺酸(AMPS)为亲水性阴离子单体、醋酸乙烯酯(VAc)和丙烯酸丁酯(BA)为疏水性酯类单体,合成了种衣剂用AMPS/VAc/BA三元共聚成膜剂。考察了AMPS、乳化剂和交联剂用量等对成膜剂性能的影响。研究结果表明,当W(复合乳化剂)=6%{其中m[乙氧基化壬基酚磺基琥珀酸半酯二钠盐(DNS-1035)]∶m[十二烷基硫酸钠(SDS)]=3∶1)、W(交联剂0.5%N,N-亚甲基丙烯酰胺水溶液)=3%和W(阴离子单体AMPS)=8%且m(VAc)∶m(BA)=1∶1时,成膜剂的性能最佳。     

Slow release of a biocidal agent from polymeric microcapsules for preventing biodeterioration

Water-soluble biocides are prone to excessive leaching and high concentrations are therefore required in surface coatings for successful protection of a surface against biodeterioration. Encapsulation prolongs the lifetime of biocides in different matrices by protecting them from leaching and by releasing them slowly. In this study, sodium benzoate as a model water-soluble biocidal agent and Congo Red dye as an capsulation indicator were incorporated into branched polyethyleneimines (PEIs) with molecular weights of 1300 and 5000 g/mol. Microscopic investigations verified that the Congo Red dye and sodium benzoate were entrapped within the capsules. The encapsulation capacity, release behaviour and efficiency of the encapsulated model biocide against two brown rot species Coniophora puteana and Serpula lacrymans were determined. The encapsulated water-soluble model biocide inhibited the growth of the decay fungi. The release of the biocide was based on slow diffusion from the capsules. The molecular weight of the encapsulated agent and the polyethyleneimine affected the release rate.     

三元复合驱含油污水油水分离剂的研制

针对三元复合驱含油污水水相粘度大、油珠粒径小和油珠聚并困难的问题，从阴离子型和非离子型药剂的思路出发，研发了促使三元复合驱含油污水兼有油珠聚结和浮选除油功能的油水分离剂Drows-1，根据Drows-1对O／W型三元复合驱采出液具有良好破乳效果的特点，提出了将油水分离剂的加药点设在三元复合驱采出液破乳之前，采用热化学沉降－浮选处理工艺解决三元复合驱含油污水油水分离问题的思路。     

缓控释肥质量快速检测方法探讨

通过缓控释肥养分释放试验,研究了缓控释肥标准检测方法与快速测定方法的差异。结果表明:供试CRF1至CRF4样品快速测定方法与标准方法误差范围为2.7%～8.3%,完全满足GB/T 23348—2009养分释放期允许误差范围25%的要求;在改变包膜材料、添加剂和喷涂温度条件下,制成的CRF5至CRF16样品采用快速测定方法用原有预测方程预测养分释放期可靠性差,表明一个预测方程不能快速准确评价所有缓控释肥。     

Thermoresponsive/low‐fouling Zwitterionic hydrogel for controlled drug release

A controlled/ living free‐radical polymerization technique was introduced to prepared a homogeneous poly(N‐isopropylacrylamide)‐g‐poly(sulfobetaine methacrylate) hydrogel (RG) possessing a highly porous architecture via two steps. Compared to a poly(N‐isopropylacrylamide)‐co‐poly(sulfobetaine methacrylate) hydrogel (CG) prepared by conventional radical polymerization, RG exhibited a much faster shrinking rate (it lost over 72% of the water in 15 min) in response to the temperature changes. The release behaviors of tetracycline hydrochloride (TCHC) of the hydrogels indicated the TCHC release from the RG could be prolonged to 48 h at 37°C; this was much longer than that for CG (5 h at 37°C). Bovine serum albumin (BSA) was chosen as the model protein to examine the low‐fouling properties of the RG. The BSA adsorption data showed that improved antifouling properties could be achieved by the RG at both 25 and 37°C. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39816.     

荧光剂生产废水新型高效组合处理方法

荧光增白剂废水对人体和环境有很大危害。采用回收废酸、H2O2、石灰等廉价试剂,通过酸性净化—微波+Fenton氧化法—碱化—生物法联合方法,处理某化工厂的荧光废水,使其COD从5 480 mg/L降至75 mg/L。该方法以废治废,生产成本低,净化效果显著。     

Synthesis of Mn-CeOx/cordierite catalysts using various coating materials and pore-forming agents for non-methane hydrocarbon oxidation in cooking oil fumes

Cooking oil fumes (COFs) as an important source of volatile organic compounds (VOCs) in metropolitan areas is poisonous to the environment and human health, and the removal rate of Non-methane Hydrocarbon (NMHC) in COFs was used to verify the activity of catalysts made to depurate COFs. The textural properties of cordierite are limitation to the catalyst's performance. Therefore, in this paper, coating the cordierite to improve its surface properties was investigated. The experiment results and characterization data revealed that TiO₂ was a better coating material because of coating on TiO₂ can improve the surface morphology better than that of Al₂O₃. The SEM and BET data of the materials synthesized with different content of CTAB showed that 10?wt% additive amount of pore-forming agent had a better textural properties than other additive amount of pore-forming agents. It is clear that the S_BET and D_V of the catalysts were significantly increased, and the catalyst exhibited smaller particle size and more developed pore structure after ultrasonic treatment which proving that ultrasound can enhance the catalyst's catalytic activity. It is obviously that the catalyst synthesized with CTAB had best pore structure and Mn₄Ce₁/Ti/NC-CTAB-U exhibited the best performance for catalytic combustion of NMHC with the removal rate was 93.6% at 400?°C.     

Degradation of polyurethane coating materials from liquefied wheat straw for controlled release fertilizers

Polyurethane (PU) was synthesized by liquefied wheat straw and isocyanates for controlled release fertilizers (CRFs). CRFs coated by PU were buried in soil for 12 months. The degradation degree and mechanism of PU coating materials were observed by thermogravimetric analysis (TGA), Atomic Force Microscope (AFM), differential scanning calorimetry (DSC), X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Fourier transform infra‐red spectroscopy (FTIR). Significant microscopic morphology of PU exhibited many small chips or stereovision holes caused by biodegradation or hydrolytic degradation due to the presence of natural polymer wheat straw. AFM results depicted the plane and height topography changes of PU before and after 12 months burial time, showing the swelling morphology of buried PU. TGA and FTIR results confirmed the disintegration of PU polymer due to the presence of isocyanates monomers in the PU12. XPS revealed an accumulation of biofilm on the surface of buried PU, providing the evidence of biodegradation mechanism. Pot experiment indicated the resin residual coating has a positive effect on soil quality. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44021.     

织物整理用IPDI/PPG封端水性聚氨酯胶粘剂的合成

以异佛尔酮二异氰酸酯(IPDI)、二羟甲基丙酸(DMPA)、聚氧化丙烯二醇(PPG)和甲乙酮肟(EMAO)为主要原料,制备封端WPU(水性聚氨酯)胶粘剂;然后采用红外光谱(FT-IR)法测得了最佳解封端温度,并以此作为焙烘温度设定的依据;最后将该WPU胶粘剂作为织物的整理剂,并对整理织物的性能进行了研究。结果表明:当R=n(-NCO)/n(-OH)=1.6、焙烘温度为150℃时,WPU胶粘剂能显著提高织物的抗皱性能和断裂强力,此时织物的折痕回复角为164.48°,经向、纬向断裂强力分别为458.33、347.67 N。     

Polyanion/gelatin complexes as pH‐sensitive gels for controlled protein release

Polyanion/gelatin complexes including poly(methacrylic acid) (PMAA)/gelatin, poly(acrylic acid) (PAA)/gelatin, and heparin/gelatin are investigated as pH‐sensitive gels for controlled protein release. Polyanions can interact with gelatin and form amorphous precipitates within a certain pH range, which is affected by the polyanion nature. The entrapment efficiency of model proteins (myoglobin, cytochrome c, and pepsin) into the complexes is rather high (>80%). By using a modified colloid titration that mixes a solution of gelatin and model proteins titrated with polyanion solution, myoglobin and cytochrome c are found to interact with polyanions by electrostatic forces at low pH, while pepsin either interacts with the polyanion when the pH is below its isoelectric point (IEP) or complexes with gelatin at a pH above IEP_pepsin. At pH 7.4 all the complexes dissociate and proteins are rapidly released within a few hours. The complexes are stable and the proteins are retained within a certain pH range, which is related to the polyanion type (e.g., 5.0–2.0 for PMAA, 4.6–1.2 for PAA, and <4.3 for heparin). The three processes of complex formation, dissociation, and protein release have a good correlation. In addition, the protein release transition takes place within a rather narrow pH range (ca. 0.5 units) and the protein nature has little effect on the protein release profile. The high protein entrapment efficiency and good pH sensitivity of the protein release can be mainly attributed to the electrostatic attractive interactions between proteins and polyanion or gelatin. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1416–1425, 2001     

聚氨酯应用于缓控释肥料无溶剂包膜的研究进展

精准施肥是当今农业绿色发展的标志性方向,缓控释肥料以可控的方式为植物提供营养的同时,最大限度减少养分损失,降低环境风险。无溶剂聚氨酯包膜材料是当前缓控释肥料研究的重要分支。为更好地掌握研究现状与发展趋势,从材料合成的角度入手,对无溶剂聚氨酯包膜的合成技术、产品种类、改性方法等方面的进展进行了分析、对比和综述。分析表明不同种类的生物质原料已被应用于包膜合成中,丰富了聚氨酯包膜的来源和种类。填充、互穿聚合物网络、有机硅等是膜材有效的改性方法。指出了简单高效的低成本改性方法,明确的控释机制及性能调控,膜材绿色环保、功能化、产业化是今后无溶剂聚氨酯包膜研究的主要趋势。