基于凹凸棒石/植物纤维复合气凝胶的香氛剂缓释性能

以凹凸棒石黏土基气凝胶为精油载体制备高载量香氛剂并实现精油长效控释。以凹凸棒石为三维网络骨架、以植物纤维为增韧补强材料,制备了一种高比表面积、高孔隙率和优良机械加工性能的的凹凸棒石/植物纤维复合气凝胶。该气凝胶对甜橙精油的负载率高达96%且挥发残油率低(<5%)。疏水改性提高了气凝胶对精油的负载率并显著延长精油缓释时间。精油挥发均呈现短暂快速下降、稳定释放、缓慢下降3段变化规律,展示复合气凝胶对精油挥发的良好控速能力：体积为4 cm3的香氛剂在60℃实验温度下可维持80 mg/h恒速释放27 h,累计释放时间为31 h;精油控释速率随气凝胶体积增大而增大,在1 cm3后逐渐趋近平台值;精油在气凝胶中的释放行为符合Korsmeyer–Peppas模型,属于Non-Fickian扩散。     

固化剂对有机改性凹凸棒石/聚苯胺环氧树脂复合涂层性能的影响

固化剂对涂层的防腐、力学性能起着至关重要的作用.以环氧树脂为成膜物质,采用原位复合法在环氧树脂体系中合成有机改性凹凸棒石/聚苯胺(OAT/PAn)复合涂层,分别使用改性脂肪胺固化剂593、酚醛胺固化剂T-31以及聚酰胺固化剂650对上述涂层进行固化,讨论了不同种类固化剂对涂层的化学结构、防腐和力学性能以及耐水性能的影响.利用FTIR 对比了各涂层的固化结构,证明了三种固化剂均可使复合涂层固化;SEM结果表明,593固化剂固化涂层的致密性最好;电化学实验结果表明,593固化剂的固化涂层防腐性能最佳,腐蚀电位达到了Ecorr=-318 mV,腐蚀电流密度Icorr=1.193×10-6 A·cm-2;通过划格法评价了各涂层的附着力,发现593固化剂固化效果最好,附着力可达5B;对比浸泡168 h后涂层的耐水性发现,593固化剂耐水性最好.     

γ-聚谷氨酸/凹凸棒石复合高吸水树脂的制备及性能

以γ-聚谷氨酸(γ-PGA)和凹凸棒石(ATP)为原料,以聚乙二醇二缩水甘油醚为交联剂,制备了γ-聚谷氨酸/凹凸棒石复合高吸水树脂,采用FTIR和SEM对其形貌和结构进行了表征。考察了γ-聚谷氨酸质量分数和凹凸棒石用量对复合高吸水树脂溶胀度的影响,发现当γ-PGA的质量分数为14%,ATP用量为6%(以γ-PGA的质量计,下同)时,样品在蒸馏水中的溶胀度较高,为820 g/g。同时,考察了溶液pH、NaCl质量分数、ZnCl_2质量分数和Na_2SO_3质量分数对复合树脂溶胀行为的影响,结果表明,适宜的pH为5～9;溶液中离子的质量分数越低,复合高吸水树脂的溶胀度越大;ZnCl_2溶液对树脂溶胀行为影响较大。此外,复合高吸水树脂具有较好的保水性能。     

PVA复合抗菌材料的现状及发展

随着新冠病毒在全球的肆虐,暴露出全球在公共卫生安全领域存在巨大的缺陷,研发出性能更优异的抗菌材料已经迫在眉睫.近年来,聚乙烯醇(PVA)抗菌材料的开发成为人们研究的热点,聚乙烯醇(PVA)抗菌材料具有独特的可生物降解性和优异的抗菌性,但是,负载抗菌剂分散困难、与基材相容性差的问题,以及其它助剂与抗菌剂的配比对抗菌材料力...     

植物精油的研究开发新进展

植物精油是一类纯天然的植物提取混合物,化学组成比较复杂.迄今为止,其在食品、医药、果蔬保鲜、日常用品、人体保健等方面得到了广泛的开发和利用.概述了植物精油及其单组分的研究利用新进展.预计不久的将来植物精油在人类生活中必将具有广阔的应用前景.     

铜改性凹凸棒石/纳米二氧化钛复合粉体的微观结构

以四氯化钛作前驱体,采用酸碱中和并流法制备了以铜改性凹凸棒石为载体的表面包覆纳米氧化钛的复合粉体.用高分辨透射电镜和X射线衍射(X-ray diffraction,XRD)对该纳米复合粉体的微观结构进行观察和分析.实验结果显示:二氧化钛以3～6nm的晶体颗粒粘附在一维纳米棒状的凹凸棒石表面.凹凸棒石和氧化钛均各自相互分离,没有团聚现象发生.纳米复合粉体中的氧化钛为单一类型的锐钛矿相,其XRD衍射峰和JCPDS的锐钛矿特征衍射峰一致.凹凸棒石的主要特征衍射峰位置没有发生较大变化.铜以多价态的形式存在于凹凸棒石表面.该复合粉体对大肠杆菌和金黄色葡萄球菌的24h抑菌率分别达到了99.52%和99.15%.     

天然苦咸水浸泡凹凸棒石的胶体性能

利用天然苦咸水浸泡凹凸棒石黏土,考察了浸泡时间对凹凸棒石黏度、流变性和悬浮性等性能的影响。结果表明,苦咸水中所含的金属离子与凹凸棒石棒晶表面离子发生了交换反应,改变了棒晶的表面电荷,从而影响凹凸棒石的胶体性能。浸泡90 d后,凹凸棒石表现出最优的悬浮稳定性,浸泡180 d后,凹凸棒石的黏度从1 188mPa·s提高到2 444 mPa·s。     

高压均质改性污泥对水煤浆成浆性的影响研究

为实现污泥的资源化利用,利用强碱性物质对污泥进行改性,通过污泥改性机的高压均质作用后将污泥掺入煤中制备高浓度污泥煤浆,研究了改性污泥对煤浆成浆浓度、黏度、流动性及稳定性等性能的影响。结果表明,0.5%Na OH加入到污泥中黏度为251 m Pa·s,1.0%Na OH添加量时污泥黏度为244 m Pa·s,过量Na OH对污泥作用不明显。经过污泥改性机高压均质后的污泥黏度为251m Pa·s,电动搅拌后的污泥黏度为337 m Pa·s,污泥改性机对污泥改性作用突出。Na OH占污泥配比0.5%,污泥添加量5%,添加剂比例0.5%,粗细粉质量比80∶20时,污泥煤浆成浆浓度最高为59.8%,流动性和稳定性均达到A级,成浆性最好。     

扩链剂TDI对PLA/AMB纳米复合抗菌材料性能影响

在聚乳酸(PLA)/自制抗菌母料(AMB)纳米复合材料中添加扩链剂甲苯二异氰酸酯(TDI),研究了TDI含量对纳米复合材料抗菌性能和力学性能的影响。结果表明,TDI质量分数在0~2.5%范围内,随着TDI含量的增加,复合材料对大肠杆菌的抗菌性能逐渐轻微减弱,但仍为强抗菌材料;拉伸强度、缺口冲击强度和弯曲强度逐渐增加,断裂伸长率先增加后减小。当TDI质量分数为2.5%时,复合材料的综合性能最好,与PLA/AMB相比,其拉伸强度、断裂伸长率、缺口冲击强度和弯曲强度分别提高了7.9%,147.6%,29.4%和22.0%,抗菌率为99.1%,仍为强抗菌材料。     

三氯生/SiO_2杂化抗菌材料的耐热性能

研究了以正硅酸乙酯(TEOS)、三氯生和γ-氨丙基三乙氧基硅烷(KH-550)为原料制备的缓释型有机/无机复合抗菌材料的耐热性能。采用SEM、FTIR和DSC/TG等方法表征了样品的颗粒形貌、表面基团和热稳定性,通过抑菌圈实验表征了经灼烧后样品的溶出抗菌性。研究发现,该有机/无机复合抗菌材料具有较好的耐热性能,于200℃加热30 min可大部分保留其抗菌性能。将该样品用于粉末涂料中,获得了抗菌率>99%的粉末涂料涂层。     

Disaggregation of palygorskite crystal bundles via high-pressure homogenization

A simple and effective method, high-pressure homogenization, for the disaggregation of palygorskite crystal bundles was reported. The effects of high-pressure homogenization on the structure and properties of palygorskite clay were investigated. The palygorskite crystal bundles were disaggregated very well while keeping the intrinsic aspect ratio of the microfibers after homogenized at 50 MPa. Compared to natural palygorskite, the specific surface area (from 192 m²/g to 246 m²/g), micropore surface area (from 72 m²/g to 110 m²/g) and micropore volume (from 0.033 cm³/g to 0.051 cm³/g) of palygorskite were clearly enhanced after homogenization. In addition, a perfect dispersion of palygorskite fibers was obtained after homogenized at 90 MPa.     

Effect of extraction methods on kinetic,chemical composition and antibacterial activities of Tunisian Thymus vulgaris. L. essential oil

The present study aims to compare two innovative extraction techniques: microwave-assisted hydrodistillation (MAHD) and solvent-free microwave extraction (SFME) through traditional extraction techniques: hydrodistillation (HD) and steam distillation (SD) for their efficiency in the extraction of the volatile compounds from Tunisian Thymus vulgaris leaves; the kinetic, yield, composition and antibacterial activities of the essential oil were assessed in vitro. Results show that the essential oils extracted by microwaves were quantitatively (yield) similar to those obtained through the conventional methods, but qualitatively, essential oils analysed by gas chromatography–mass spectrometry (GC–MS) presented 17, 11, 11 and 8 compounds obtained through SFME, MAHD, SD and HD, respectively, mostly consisting of carvacrol (89.24–41.17%), followed by γ-terpinene (11.37–1.37%) and para-cymene (27.95–2.05%). The essential oils were screened for antibacterial activity against 5 microorganisms. All essential oils obtained by studied extraction methods showed the same resistance against Gram (?) and Gram (+) bacteria. The SFME method gave the best results: rapid kinetic of extraction (30 min vs. 35 min for MAHD, 120 min for SD, and 180 min for HD), less energy saving and cleanest process.     

植物精油的抑菌性探究及其在化妆品中的应用

通过6种精油抑菌性试验,发现肉桂精油、玫瑰精油、甜橙精油具有较好的抑菌性,其中含有高含量醛的肉桂精油抑菌效果最好。研究了在膏霜中添加肉桂精油对防腐体系的影响,实验结果表明:在未添加肉桂精油的膏霜中,防腐剂的用量需添加至0.25%才能对细菌和真菌有较好的抑制效果;在添加了0.01%的肉桂精油的膏霜中,防腐剂的用量只需添加0.1%就能对细菌和真菌有较好的抑制效果。这说明肉桂精油可以降低化妆品中防腐剂的用量。通过皮肤刺激性试验,发现在均能通过防腐测试的前提下,添加了0.01%肉桂精油和0.15%防腐剂的膏霜L/D值为112.26,而只添加了0.25%防腐剂的膏霜L/D值为58.53,说明在化妆品中添加肉桂精油,在降低了防腐剂用量的同时,也降低了化妆品的刺激性。但是,当防腐剂用量均为0.15%时,添加了肉桂精油的膏霜L/D值比未添加肉桂精油的膏霜L/D值略低,这说明肉桂精油本身具有轻微的刺激性。     

植物精油提取新技术的研究进展

随着化工分离技术研究的不断深入,植物精油的提取技术也得到了进一步发展,出现了很多新的提取技术和方法。介绍了植物精油的提取技术,包括超临界CO~2萃取、连续亚临界萃取、微波萃取、微胶囊双水相萃取、超声波萃取、分子蒸馏、酶法提取等方法,对这些技术进行了分析,同时展望了植物精油提取技术的发展前景。     

Influence of calcium and magnesium content of coconut oil on deposit and performance of plant oil pressure stoves

The influence of calcium and magnesium content of plant oil on performance and formation of deposits in plant oil pressure stoves was the objective of this study. Refined coconut oil of pharmaceutical quality was used as base for fuel blends. Enriched oils comprising four different concentrations of calcium CC and five different concentrations of magnesium MC were prepared by adding single element organometallic standards. During burning tests, the specific fuel consumption, the required frequency of nozzle cleaning and the amount of deposits in the vaporizer were measured.Deposits DEP increased as the level of calcium in the fuel blends increased to 0.17 g/kg for the control and reached 10.08 g/kg for the test fuel CC42. The same was also valid for magnesium-enriched fuel blends. However, reduced concentrations of earth alkaline lead to a higher amount of deposits with 11.94 g/kg for MC18.For CC5, CC10 and CC26 the specific fuel consumption was in a range between 0.266 and 0.294 kg/h, with CC42, being significantly reduced to 0.207 kg/h. Test fuels enriched with magnesium showed a similar behaviour, where a reduction of the specific fuel consumption for the high magnesium contents of MC18 and MC26 was observed.     

Influence of free fatty acid content of coconut oil on deposit and performance of plant oil pressure stoves

In tropical and subtropical countries, utilization of unprocessed plant oil or used frying oil as household cooking fuel promises to be a competitive alternative to well known fuels like wood and kerosene. However, the use of unprocessed plant oil in plant oil pressure stoves leads to the formation of deposits inside the vaporizer, which have to be removed from time to assure a proper operation of the plant oil pressure stove.Therefore, the objective of this study was to investigate the effect of free fatty acid content of coconut oil on performance and deposit formation in plant oil pressure stoves. Test fuels with different levels of free fatty acid content were prepared by aerating the coconut oil with dry air (5.04 l O₂/kg h) at a temperature of 85 °C. Experiments were performed with the plant oil pressure stove ’Protos’ (BSH Bosch und Siemens Hausgeräte GmbH).As a result, 0.15 g of deposits per kg of consumed oil was found for fresh coconut oil with free fatty acid content of 0.03%, which served as control. Aged oil with a free fatty acid content of 23.1% resulted in 6.48 g deposits per kg of consumed test fuel. Conradson carbon residue CCR of 0.18% was low for control and increased to 0.82% for aged oil. Specific fuel consumption was in a range between 0.284 and 0.304 kg/h without significant differences between the fuels. Performance of the plant oil pressure stove was not affected by the amount of free fatty acids in the plant oil. However, lower heating value decreased from initial 35 MJ/kg for control to 30 MJ/kg for aged fuel, and as consequence power output from plant oil pressure stove decreased. Therefore, plant oils with free fatty acid content below 5%, which is equivalent to an acid value of 10 mg KOH/g, are recommended as fuels for plant oil pressure stoves.     

茅莓根和叶挥发油抑菌活性的研究

通过最小抑菌浓度试验，研究茅莓根和叶挥发油的抑菌活性。结果表明，茅莓叶对对大肠杆菌、巴氏杆菌有明显的抑菌活性，最小抑菌浓度（MIC）分别为10^-7g/mL、10^-6g/mL，优于链霉素（10^-3g/mL、10^-5g/mL）和黄胺类（10^-4g/mL、10^-6g/mL）。     

鱼鳞明胶/壳聚糖/薰衣草精油抗菌复合膜制备及性能

以鱼鳞明胶(SG)和壳聚糖(CS)为原料,薰衣草精油(LEO)为抗菌剂,通过共混法制备抗菌复合膜,通过FTIR、XRD、SEM和热重分析对复合膜的形貌和结构进行表征及对力学、光学、阻隔、抑菌等性能测试分析。结果表明,LEO与SG/CS基膜较好复合,与SG/CS基膜相比,当LEO添加量为1%时,复合膜具有良好的力学强度(26.36 MPa),断裂伸长率提升了12.96%；透明度有所下降,透光率为70.50%；耐水性能和水蒸气阻隔性能显著增强,含水率、水溶性和水蒸汽透过率分别下降了22.48%、30.49%和26.03%；DPPH自由基清除率提高了247.88%,抗氧化性显著提高；同时对大肠杆菌和金黄色葡萄球菌具有良好的抑菌作用。     

Preparation of novel Cu/TiO2 mischcrystal composites and antibacterial activities for Escherichia coli under visible light

In this paper, novel copper/titanium dioxide (Cu/TiO₂) composites were facilely prepared by simple sol-gel hydrothermal method. The crystalline phases, surface morphology and antibacterial activity of Cu/TiO₂ were investigated systematically. Interestingly, the as-prepared Cu/TiO₂ materials were made up with three different crystalline phases, including cuprite Cu₂Cl(OH)₃, Cu₂₊₁O, and anatase TiO₂. Next, the ‘zone of inhibition’ experiment was performed against E. coli using Cu/TiO₂ catalysts with different Cu doping concentration as the antibacterial agents. Our results show that the Cu/TiO₂-3.00 catalyst possesses optimal antibacterial ability against E. coli, which may be connected with the strong oxidizing reactive oxygen species (ROS) destroying the bacteria and photogenerated charge separation and recombination.