粘土中金属组分对天然橡胶／粘土复合材料老化性能的影响

通过还原剂、强酸及添加金属化合物的方法处理３种粘土,并制备相应的粘土胶进行热氧老化性能测试。结果表明,粘土中的铜、锰、钴、铁４种金属组分对粘土胶老化性能产生影响,其中,以钻最为显著,其次是铜,最后是铁和锰。在一定范围内,铁含量变化对粘土胶老化未产生明显作用。由于金属组分在粘土中存在形式的差异,使粘土胶的老化性能与粘土中有害金属含量不存在对应关系。     

不同生产工艺对天然橡胶臭氧老化性能与结构的影响

胶乳的凝固和干燥是天然生胶生产的重要环节。在不同凝固方式（酸凝固、微波凝固、自然凝固、微生物凝固）、不同干燥方式（自然风干、热风干燥）等不同工艺下研究了天然橡胶（NR）的理化性能及其臭氧老化前后物理机械性能,发现微生物凝固胶在相同臭氧老化条件下其拉伸强度最高,且变化率最低。采用臭氧老化研究的结果表明：微生物凝固胶（m-NR）硫化胶在静态拉伸状态下臭氧龟裂达到16 h。热重分析探讨了不同工艺NR硫化胶热老化过程,并采用衰减全反射傅立叶红外光谱（FTIR-ATR）技术初步探讨了臭氧对微生物凝固胶的老化作用。     

海南岛橡胶园土壤粘土矿物组成与土壤电荷量

对海南岛14个胶园土壤中粘土矿物组成及土壤表面电荷量进行了研究.结果表明:①供试胶园土壤粘土矿物以高岭石为主,部分土壤中还含有水云母、1.4 nm矿物及三水铝石.各粘土矿物组分含量因气候生态区、发育母质及地形而异;②胶园土壤表面以负电荷为主,负电荷量随土壤pH值的升高而增加,表明其为可变负电荷:③橡胶园土壤正电荷量少,且随pH值升高而减少;④低pH值时,不同母质发育的土壤正电荷量大小顺序为:玄武岩>浅海沉积物>花岗岩和砂页岩.     

丙酮溶物对天然橡胶臭氧老化性能影响

天然橡胶中的非胶物质种类和含量影响橡胶的质量和应用性能。本文通过硫化性能、交联密度、耐臭氧老化 性能测试和热重分析研究丙酮溶物含量对天然橡胶臭氧老化性能的影响。结果表明,丙酮溶物可以改善天然橡胶的硫 化性能,提高其交联密度。随着丙酮溶物添加量的增加,天然橡胶的热稳定性、臭氧裂纹显现时间、拉伸强度保持率 逐渐提高并达到最大值。采用衰减全反射傅里叶红外光谱分析仪（ATR-FTIR）分析了天然橡胶臭氧老化前后分子结构 变化,可知橡胶在臭氧老化后出现了氧化官能团。     

微波干燥对天然橡胶硫化胶热氧老化性能的影响

研究3种不同干燥方式所得天然橡胶硫化胶的热氧老化性能。采用TG和DTG测定了空气氛围下干燥后样品硫化胶的热氧降解温度,运用Coats-Redfern方程计算N2氛围下样品硫化胶热降解活化能;采用RPA 2000在应变为0.5 deg下进行频率扫描来评估样品耐热老化性能,并测定了样品硫化胶老化前后的力学性能。结果表明,微波干燥天然橡胶的力学性能明显优于热空气干燥和自然干燥,性能变化率和老化系数更大,样品RPA频率扫描tanδ值的增值更大,微波干燥样品的热降解活化能高于热空气干燥9 kJ/mol,与自然干燥样品接近,说明微波干燥天然橡胶硫化胶的热稳定性好,耐热氧老化性能得到显著提高。     

品系对天然橡胶臭氧老化性能的影响

对比分析5个栽培条件相近主栽品系的天然橡胶的结构与性能差异,发现RRIM600性能最好,拉伸强度达30.21 MPa,耐臭氧老化性能最优。通过分析非胶组分,结合ATR-FTIR与热重分析仪器初步探究其耐臭氧老化差异的原因:RRIM600橡胶树生产的橡胶非胶组分杂质与灰分含量低,蛋白质含量适中,P0、PRI较高,分子链结构规整,橡胶中含有较多的胺基抑制臭氧化反应,使得分子链受到保护,综合表现出较好的耐臭氧性能。     

环氧化天然胶／丁腈胶共混物耐热氧老化稳定性研究

采用差示扫描量热计,强力试验机,老化烘箱等设备研究环氧化天然胶(ENR)/丁腈胶(NBR)共混物的耐热氧老化稳定性。结果表明:对于50/50比例ENR/NBR共混物,其老化机理属于硬化劣变型,促进剂、防老剂、补强填充剂的种类和用量对共混物的热氧老化稳定性均有较大影响。通过试验所选取的配方可有效地保证ENR/NBR共混物具有良好的耐热氧稳定性,能广泛应用于工业上。     

锰离子对天然橡胶老化性能的影响

研究锰离子含量对天然橡胶(NR)热氧老化、紫外老化和臭氧老化前后性能的影响,并采用核磁交联密度分析仪、DSC分析仪和傅里叶红外分析仪探究老化前后分子链结构的变化。结果表明,在老化之前,含有不同量的锰离子的天然橡胶的物理机械性能基本一致。经3种方式老化后的胶样性能均有不同程度的下降,当锰离子质量分数为0.000 30%时,天然橡胶老化后的拉伸强度、300%定伸应力、700%定伸应力下降程度最小。核磁交联密度测试表明,总交联密度(XLD)与网链分子量(Mc)有很好的对应关系,XLD随着锰离子质量分数的增加而先增大后减小,表明天然橡胶老化过程中交联反应和断裂反应存在竞争关系。示差扫描量热(DSC)测试发现,随着锰离子质量分数的增加,天然橡胶的玻璃化转变温度(Tg)先升高后降低,与核磁交联密度测试结果一致。红外分析(FTIR)发现,天然橡胶老化过程中发生了交联和断裂反应。     

KJ—1高效澄清剂在制糖生产中的初步应用

KJ-1高效澄清剂是一种用海洋生物提取高分子生物制品，无毒、无味、可食用。具有很强的吸附性。生产实践证明，在亚法糖厂澄清工艺中使用KJ-1高效澄清剂，能够改善澄清性能，提高产品质量，减少硫磺、石灰使用量。     

乳清蛋白对天然橡胶性能的影响

通过外加乳清蛋白的方式研究了蛋白质对天然生胶理化性能和硫化胶的力学性能、老化性能、硫化特性、交联密度及动态热机械性能的影响。结果表明:天然生胶中加入乳清蛋白后,随着蛋白质含量的增加,门尼粘度升高,正硫化时间缩短,硫化胶的力学性能及热老化性能提高;在测试范围内,硫化胶的交联密度升高,储能模量和玻璃化温度都随着蛋白质含量的增加而增大。     

环氧化天然橡胶对天然橡胶/白炭黑湿法母炼胶性能的影响

将乳胶状的环氧化天然橡胶(ENR)作为界面改性剂应用于NR/白炭黑的湿法混炼,通过对比ENR改性处理的湿法母炼胶(NES)和未经改性处理的湿法母炼胶(NS),研究ENR对湿法母炼胶性能的影响。结果表明:胶料中的填料-填料网络主要是在硫化初期填料絮凝而形成,通过热处理能够降低NES的填料絮凝速率。与NS相比,不管有没有偶联剂存在,NES均具有更低的絮凝速率常数和由此导致的更弱的填料-填料网络;随着偶联剂用量的增加,胶料的300%定伸应力和耐磨性提高,且NES的提高幅度更大。分析认为,ENR一方面在白炭黑表面形成聚合物层,防止填料的絮凝;另一方面能够与硅烷偶联剂起协同作用改善填料-橡胶界面结合。     

Synthesis of high performance phosphorine antioxidants and their application to mCOC

Cyclic olefin copolymers, mCOC, produced using a metallocene catalyst, have been developed since 1990. Besides their high cost and difficulty of processing, oxidation and degradation are one of the critical problems in commercializing high-T_g mCOC products. In this work, a series of mCOCs whose T_g values were 132 °C, 194 °C and 260 °C were synthesized successfully. Additionally, high-performance phosphorine antioxidants, 1,4-di[6-oxo-dibenz[c,e][1,2] oxaphosphorine] benzene (HPB) and 2,5-di-tert-butyl-1,4-di[6-oxo-dibenz[c,e][1,2] oxaphosphorine]benzene(HTPB) were synthesized. The oxidation induction time (OIT), the carbonyl index (CI) and the yellowness index (YI) were determined by DSC, FTIR and spectrophotometry, respectively. The results indicate that blending phosphorine antioxidants with hindered phenolic antioxidant, increases the OIT from 31.8 to 44.1 mins and causes the synergy to exceed 180 %. The CI variation showed that the embrittlement time could be increased from 100 hrs to over 450 hrs by thermal aging at 140 °C. Finally, the YI dropped from 29.3 to 9.2. Briefly, HTPB and HPB, successfully synthesized herein, exhibit a synergy with hindered phenolic agents in antioxidant performance for mCOC polymer.     

Functionalization of lyocell fibers with TiO2, SiO2, and GLYMO

In the research self-cleaning coatings based on photocatalytically active nano titanium dioxide (TiO₂) were prepared. When applied directly to cellulose fiber surfaces, TiO₂ coatings form weak bonds with fibers. Therefore 3-glycidooxypropyl-trimethoxysilane was used as a coupling agent. It had been applied on the surface of cellulose fibers before the TiO₂ coating was performed. In this case, the silane is in the interface region, where it can be most effective as an adhesion promoter. Silane coupling agents have unique chemical and physical properties not only to enhance bond strength, but more importantly to prevent de-bonding at the interface during composite aging and use as well. The coupling agent provides a stable bond between two otherwise poorly bonding surfaces. Surface properties of these coatings have been examined, such as surface morphology and surface microstructure. TiO₂ nanoparticles were irreversibly attached to the surface of monodisperse silica (SiO₂) spheres and to the surface of Lyocell fibers coated with an epoxy-containing silane coupling agent. Analysis using scanning electron microscopy showed uniform distribution of nanoparticles in the resulting coatings. Fourier transform infrared spectroscopy revealed changes in the surface microstructure occurring after different modifications. In addition, the influence of photocatalytic activity on the mechanical properties of Lyocell fibers was determined. In addition to that, the results indicated that SiO₂ and the coupling agent provide a protection against high oxidizing power of TiO₂ under exposure to daylight irradiation.     

种衣剂减量下增施菌剂和肥料对小麦光合、产量、蚜虫及白粉病防控的影响

为探究拌种药剂减量下增施不同类型肥料对麦田蚜虫和白粉病防控及光合和产量的影响,以小麦蚜虫低感品种川麦104和高感品种内麦836为试验材料,采用大田试验,对种衣剂减量20%下,配合施用光合菌剂、微生物菌剂、硅肥或磷酸二氢钾后麦田土壤酶活性、小麦植株光合特性、病虫防治情况和产量性状的变化进行了比较分析。结果表明,拌种药剂减量20%条件下增施微生物菌剂较种衣剂常规用量处理能显著提高孕穗期川麦104的根际土壤的脲酶活性,以及内麦836的根际土壤过氧化氢酶和纤维素酶活性。在孕穗期和抽穗期,低感品种川麦104的麦蚜数量均显著低于内麦836;增施微生物菌剂和硅肥均能显著降低麦蚜和白粉病发生,对蚜虫防效和白粉病防效较常规药剂拌种用量处理分别提高8.0和10.2个百分点。拌种药剂减量20%配合施用光合菌剂、微生物菌剂、硅肥和磷酸二氢钾均能有效提高小麦旗叶氮素含量和SPAD值,改善叶片光合效率。增施硅肥下川麦104和内麦836的产量最高,较常规种衣剂用量处理分别增加16.0%和18.2%,差异均显著。以上结果说明,小麦种子种衣剂减量配合施用硅肥或微生物菌剂可有效提高麦田土壤酶活性,减少蚜虫和白粉病发生,改善小麦叶片光合特性,提高产量。     

Evaluation of Food Conservation Technologies for Potato Cubes

Potato cubes of cultivar Innovator were subjected to different food conservation treatments: osmotic dehydration and antioxidants (OD + A), edible coating (E), edible coating with osmotic dehydration and antioxidants (EC + OD + A), immersion in antioxidants (A) and microwave blanching (B). The quality of the products was evaluated by measuring dry matter content, colour, browning index, total phenols and antioxidant capacity and polyphenol oxidase (PPO) activity. Treatments with A resulted in a lower a* colour parameter (red to green) but increased total phenols and antioxidant activity. Those treatments with OD and A together resulted in even larger increases in total phenols and antioxidant activity and also reduced PPO to negligible activity. OD increased dry matter content in OD + A treatments. B increased the browning index (BI) and colour parameters a* and ΔE (total change). As a consequence, potato cubes treated with osmotic dehydration and antioxidants had improved quality characteristics and these treatments are appropriate for minimally processed vegetables.     

环氧化天然胶乳改性陶土对天然橡胶硫化胶的作用研究

以环氧化天然胶乳（ENRL）作为陶土的改性剂。采用IR并结合胶含量、表现交联密度、界面作用强度表征值、蠕变和力学性能测定,研究了ENRL对陶土的改性作用及其对天然橡胶硫化胶性能的影响。结果表明,ENRL对陶土具有较好的改性效果。环氧化程度较高的ENRL,最适宜用量较低;环氧化程度较低的ENRL,最适宜用量较高。ENR15为17．5％ENR25为15％ENR35为12．5％,ENR45为10％。以最适宜用量的ENRL对陶土的改性效果以ENR25较好,ENR15、ENR35次之,ENR45较差。     

天甲橡胶改性陶土与NR的相互作用

用天甲橡胶(MG49)改性陶土。通过IR、SEM及结合胶含t、表观交联密度、界面作用表征值、姗变和力学性能的测定,研究改性陶土与NR的相互作用及改性效果。结果表明:MG49湿法改性陶土提高了混炼胶的结合胶含量,增加了材料的表观交联密度,增强了陶土与NR间界面的作用强度,改善了硫化胶的网络结构,提高了硫化胶的力学性能     

Biodegradable tocopherol acetate as a drug carrier to prevent ureteral stent-associated infection

Biomaterial-centred bacterial infections present common and challenging complications with medical implants like ureteral stent which provide substratum for the biofilm formation. Hence the purpose of this study is to make antibacterial stent surface with biodegradable polymer (tocopherol acetate) and anti-infective agents (norfloxacin and metronidazole) using a modified dip-coating procedure. This is done by impregnating the stent pieces in the anti-infective solution (a mixture of norfloxacin-metronidazole and polymer) for uniform surface coating (drug-carrier-coated stents). After coating, agar diffusion test was performed as qualitative test to find out the sensitivity of coated stents against the clinical isolates, Staphylococcus epidermidis and Escherichia coli. Quantitative test was measured by calculating the numbers of adhered bacteria on coated and uncoated stents by incubating the stent pieces in artificial urine. Difference in the number of viable bacteria adhered on the surface of coated and uncoated stents were statistically calculated using chi square test with p < 0.05 considered significant. The stent colonising ability of Staphylococcus epidermidis and Escherichia coli in a controlled environment chamber was determined using two-challenge dose of the isolates by in vitro challenge test. In qualitative test, the zone of inhibition around the coated stents showed sensitivity against the clinical isolates. In quantitative test, the number of adhered bacteria on the surface of coated stents was reduced to a significant level (p < 0.05). The polymer, tocopherol acetate is highly biodegradable in nature. Due to its degrading ability in body tissues, it releases the anti-infective drugs at a constant and sustained rate.     

Effect of nano SrTiO3 supporting nano TiO2 on self-cleaning of cotton fabric

This study reports the results of an investigation aiming at finding what affect nano titania (TiO₂) and nano strontium titanate (SrTiO₃) on self-cleaning of cotton fabrics. The photocatalytic activity of nano strontium titanate has been examined on cotton fabric under UV irradiation in various concentrations in mixing of nano titania. The amount of loaded nano titania and nano strontium titanate particles on cotton fabrics were investigated using X-ray fluorescence spectrometry (XRF) and crystallinity of coatings by X-ray diffraction spectroscopy (XRD). The treated cotton fabrics, which were stained with two common synthesized dyes, were exposed to 400 W UV radiation for 30 hours and their self-cleaning property was investigated by a reflectance spectrophotometer. Scanning electron microscope (SEM) images show pervasion of nano materials on the surface of the treated cotton. Adding nano strontium titanate to nano titania showed the most promising photocatalytic activity toward dye degradation.