聚丙烯酸-g-非离子性聚氨酯在复鞣中的应用(续)

以丙烯酸(AA)与可聚合非离子性聚氨酯表面活性剂(PUA)为原料,通过自由基共聚制备了一种阴非离子性的多功能型树脂复鞣剂,采用FT-IR、DSC对其分子结构进行了表征,并将其应用于复鞣工序。研究结果表明:共聚物组成对该类接枝共聚物的实际复鞣效果影响显著。其中m(AA)∶m(PUA)为1∶1.5的共聚物Ⅳ,具有更好的填充增厚性和丰满性;而m(AA)∶m(PUA)为1∶19的共聚物Ⅱ则具有更好的助染性,成革的柔软度和粒面效果更佳。     

聚丙烯酸-g-非离子性聚氨酯在复鞣中的应用

以丙烯酸(AA)与可聚合非离子性聚氨酯表面活性剂(PUA)为原料,通过自由基共聚制备了一种阴非离子性的多功能型树脂复鞣剂,采用FT-IR、DSC对其分子结构进行了表征,并将其应用于复鞣工序。研究结果表明:共聚物组成对该类接枝共聚物的实际复鞣效果影响显著。其中m(AA)∶m(PUA)为1∶1.5的共聚物Ⅳ,具有更好的填充增厚性和丰满性;而m(AA)∶m(PUA)为1∶19的共聚物Ⅱ则具有更好的助染性,成革的柔软度和粒面效果更佳。     

两性丙烯酸树脂复鞣剂的合成及应用

以丙烯酸 (AA)和甲基丙烯酰氧乙基三甲基氯化铵 (DMC)为原料 ,在水中采用自由基共聚和制备了两性丙烯酸树脂复鞣剂。利用红外光谱 (FTIR)和核磁共振 (13 CNMR)对其结构进行了表征。分别采用浊度法和黏度法测定了该类聚合物的溶解性和黏度行为。应用试验表明 ,共聚物的复鞣性能与其组成和分子量大小有关 ,在丙烯酸聚合物鞣剂中引入阳离子基团 ,可以提高复鞣革的柔软度 ,克服败色现象。通过扫描电镜观测、X -衍射分析证实 ,两性丙烯酸树脂复鞣剂可以分散皮胶原纤维 ,降低胶原纤维的结晶度。     

PR—1共聚物复鞣剂的研究

以水作溶剂,过氧化物为引发剂,用顺丁烯二酸酐和乙烯基类为单体。合成多元共聚物(PR—1)复鞣剂。PR—1属多官能团聚离子型复鞣剂,试产品经成都、四川、浙江、河南、山东、新疆等地制革厂家应用结果表明,PR—1是制造猪、牛、羊软革产品的优良复鞣剂。它具有使成革丰满、柔软、增厚明显。粒面细致、毛孔清晰、pH值使用范围宽,对染色影响小等优异性能。复鞣剂主要有天然聚合物及其改性产品和合成聚合物两大类。合成聚合物主要有聚丙烯酸类,聚氨酯类和顺丁稀二酸酐的共聚物。顺丁烯二酸酐与芳烃共聚物由于用芳烃作溶剂,有机过氧化物作引发剂,该产品不仅对环境带来污染而且成本高,使用受到限制。PR—1顺丁烯二酸酐与乙烯基单体共聚物采用水作溶剂,生产过程基本无三废,还具有原料成本低且性能优异的特点。     

磷脂加脂复鞣剂PMS的制备

以丙烯酸和马来酸酐为原料合成出了一种共聚物。用该共聚物对磷脂进行酰化，制备出了一种新的加脂复鞣剂。应用研究结果表明，该加脂复鞣剂具有良好的乳化性能和乳液稳定性，用于铬复鞣或加脂工序，能增加革的丰满度、柔软度、抗张强度和伸长率。当用于铬复鞣工序时，还能大幅度提高铬的吸收率。     

丙烯酸与甲基丙烯酸共聚物分子质量的控制研究

合成了水溶性丙烯酸(AA)和甲基丙烯酸(MAA)共聚物复鞣剂,通过测定共聚过程中体系黏度的变化,研究了影响分子质量的主要因素及控制分子质量的方法。对所合成的共聚物的复鞣性能进行了初步的探讨。该工艺操作简便、安全可靠,已实现工业化生产。     

SAB复鞣剂的研制

本文制得了异相酸降解淀粉和丙烯酰胺－丙烯酸丁脂共聚物。通过该共聚物酰胺基的Hoffman反应使上述降解淀粉和共聚物进行了接枝共聚;利用正交试验确定了此接枝反应的条件。研究结果表明：通过Hoffman反应能成功地使二者接枝共聚,同时实现阳离子化。根据以上结果合成出了SAB复鞣剂,并将它用于山羊蓝湿服装革的复鞣。结果表明：SAB复鞣剂具有一定的填充作用,与染料、油脂的协同作用好;经SAB复鞣剂复鞣后的环革柔软、丰满、有弹性、表面着色均匀浓厚,并可基本保持坯革的物理机械强度。     

分子复合聚合物复鞣剂MBN

根据超分子科学原理 ,使带阴电荷的共聚物 MA- AA与带阳电荷的 12 31进行分子复合 ,制备具有超分子结构的聚合物复鞣剂 MBN。由于结构的独特性 ,经成革试验表明 ,它具有优良的复鞣效果。     

改性丙烯酸树脂复鞣剂的结构与性能研究

采用硫酸化不饱和动植物混合油(简称硫酸化不饱和油)、(甲基)丙烯酸、丙烯酸酯作为共聚单体,通过乳液聚合制备改性丙烯酸树脂复鞣剂乳液(简称改性复鞣剂)。分别用FTIR、DSC、万能试验机、旋转黏度计、TEM,测试了复鞣剂成膜物及乳液的结构、热性能、力学性能、旋转黏度以及复鞣剂的形态。此外,通过实验研究了产品的物理性能和化学反应性。最后,还通过应用试验考察了丙烯酸树脂复鞣剂与本产品的复鞣性能。结果表明:纯化样品在1058~1062 cm~(-1)处出现S=O特征吸收峰,验证了硫酸化不饱和油与丙烯酸类聚合物进行了部分接枝共聚。引入硫酸化不饱和油可以适当降低复鞣剂成膜物的玻璃化转变温度(Tg),其Tg在pH 3~5时,随pH升高而升高。引入铬粉的复鞣剂成膜物Tg亦明显提高。吸湿后的成膜物弹性增强,柔软性良好。采用适量NaOH溶液中和会使产品抗张强度增大,断裂伸长率增加。该种复鞣剂微粒近似球形,粒度分布均匀,中和后平均粒径由72nm减小为66 nm。应用试验表明,改性复鞣剂综合性能较丙烯酸树脂复鞣剂乳液更佳。     

氧化降解淀粉与乙烯基单体接枝共聚物复鞣剂的合成及应用研究

经过氧化降解的玉米淀粉与乙烯基单体丙烯酸（AA)和丙烯腈（AN）在Fe^2 -(NH4)2S2O8氧化还原引发剂作用下进行了接枝共聚合反应，制得了改性淀粉复鞣剂。研究了单体浓度及配比、引发剂浓度等因素对接枝共聚合反应的接枝率、单体转化率、接枝效率等的影响，用红外光谱对接枝共聚物的结构进行了分析表征，同时进行了复鞣剂应用实验。     

新型阳离子染料皂洗剂的合成及应用

以马来酸酐(MA)、丙烯酸(AA)和丙烯酸十八酯(SA)为原料,采用偶氮二异丁氰作为引发剂,在乙醇介质中,共聚生成了较高相对分子质量和高羧基电荷密度的聚马来酸酐-丙烯酸-丙烯酸十八酯(MA-AA-SA)三元共聚物PMAS,并将其用于腈纶织物染色后的皂洗工序中.通过探讨单体配比、引发剂用量、反应时间和皂洗剂用量等因素对皂洗性能的影响,得到优化的合成工艺条件为:m(MA)∶m(AA)∶m(SA)=2∶6∶2.5,ω(引发剂)=2.5％(相对于原料的质量分数),反应温度65℃,反应时间7h;应用试验表明,PMAS用量为2 g/L时,皂洗效果最佳,织物皂洗后湿摩擦牢度达4～5级,干摩擦牢度达5级,且具有良好的防沾色性能.     

聚合型多元羧酸的合成及其在柞丝绸防皱整理中的应用研究

合成马来酸（MA）、依康酸（IA）共聚物（PMI），用于柞丝绸的抗皱整理，通过正交试验优选了其在柞丝绸防皱整理中的应用工艺，结果表明：织物经PMI整理后，湿弹性显著提高，耐洗性较好，对织物的白度和强度基本无影响。     

Inhibition of Listeria monocytogenes and Salmonella by natural antimicrobials and high hydrostatic pressure in sliced cooked ham

The effectiveness of nisin, lactate salts, and high hydrostatic pressure to inhibit the growth of Listeria monocytogenes and Salmonella in sliced cooked ham was studied through a combination of PCR-based detection methods, most probable number, and classical microbial enumeration techniques (International Organization for Standardization protocols). A synergistic effect to inhibit a cocktail of Listeria monocytogenes CTC1010, CTC1011, and CTC1034 was observed between potassium lactate, high hydrostatic pressure (400 MPa, 17 degrees C, 10 min), and low storage temperature when sliced cooked ham was stored for 84 days at 1 degrees C. The high hydrostatic pressure treatment also proved to be useful to inhibit a cocktail of Salmonella enterica serotypes London CTC1003, Schwarzengrund CTC1015, and Derby CTC1022.     

乙烯基类聚合物鞣剂共单体种类配比与应用性能相关性的研究

采用单因素二次回归正交试验研究了乙烯基类聚合物鞣剂共单体种类、配比与应用性能的相关性,通过比较不同共单体及其不同配比的乙烯基聚合物鞣剂复鞣革样与对比革样的性能,得到了不同共单体对鞣剂应用性能的贡献。结果表明：含极性基团的共单体有利于复鞣革样抗张强度、耐湿热稳定性的提高,但影响革样的柔软性和革样胶原纤维的柔韧性;共单体丙烯酰胺对复鞣革样的丰满性具有特殊的贡献,鞣剂分子中引入丙烯酸酯类共单体有利于复鞣     

Tetracyclines and their metabolites in egg white and yolk

 4-Epimers of tetracycline (TC) and chlortetracycline (CTC) were formed in vivo in laying hens and excreted in substantial amounts besides the residues of the administered parent compounds via the egg. The recent observation of isochlortetracycline (i-CTC) and its 4-epimer as being the principal metabolites in eggs after feeding CTC could be confirmed. The ratio of 4-epimer to parent compound of TC, CTC and i-CTC was lower in egg white and higher in yolk and did not change during medication with TC or CTC. Further, yet unidentified, in vivo formed metabolites were observed. Received: 27 July 1998     

Studies on Thearubigin Pigments in Black Tea Manufacturing Systems

The formation of thearubigin pigments in prevalent commercial manufacturing systems such as orthodox roll, roll followed by curling, tearing, crushing (CTC), rotorvane combined with CTC and CTC alone was studied in the six Tocklai released clones TV-1, TV-2, TV-8, TV-9, TV-17 and TV-18. The contribution of the pigment composition, especially thearubigins of high, intermediate and low molecular weights as separated by a Sephadex LH 20 column, was examined on the basis of the types of leaves, degree of wither and roll, conditions of fermentation and the temperature and type of drying. It was apparent that the biochemical pathway in the black tea processing could be conveniently followed from the thearubigin formation. Further, the amount of high molecular weight thearubigin could determine the quantity of cream formed in a black tea brew. The thearubigin and concomitant pigments such as theaflavin have distinct organoleptic properties and their variation was reflected in the overall quality of the finished product.     

Tetracyclines and their metabolites in egg white and yolk

 4-Epimers of tetracycline (TC) and chlortetracycline (CTC) were formed in vivo in laying hens and excreted in substantial amounts besides the residues of the administered parent compounds via the egg. The recent observation of isochlortetracycline (i-CTC) and its 4-epimer as being the principal metabolites in eggs after feeding CTC could be confirmed. The ratio of 4-epimer to parent compound of TC, CTC and i-CTC was lower in egg white and higher in yolk and did not change during medication with TC or CTC. Further, yet unidentified, in vivo formed metabolites were observed.     

Chlorophylls and degradation products in orthodox and CTC black teas and their influence on shade of colour and sensory quality in relation to thearubigins

Chlorophylls and concomitant pigments along with catechins were analysed in shoots from various Tocklai released clones with pronounced genetic variation and in the corresponding orthodox black teas. Comparison of these values with tasters' score showed that the shade of colour of an orthodox black tea is influenced mostly by pheophytin and thearubigins. The degradation of chlorophyll into pheophytin and pheophorbide was also studied in orthodox and crush - tear - curl (CTC) teas. The observations indicated that both pheophytin and pheophorbide are always higher in orthodox than in CTC teas made from the same leaf source.     

Excretion of tetracycline and chlortetracycline in eggs after oral medication of laying hens

After dosing laying hens orally with tetracycline (TC) through either drinking water (0.25 and 0.5 g/l for 5 days) or feed (300 and 600 ppm for 7 days), and chlortetracycline (CTC) through feed (600 ppm) residues were determined by an agar plate diffusion technique in cylinders with Bacillus cereus as test-organism, separately for albumen and for yolk. The sensitivity threshold was 0.07 micrograms/g in albumen and 0.15 micrograms/g in yolk for TC and 0.01 micrograms/g in albumen and 0.06 micrograms/g in yolk for CTC. Drug excretion via egg was 3-fold higher for TC than for CTC. The drug was excreted preferentially into the yolk (about 75% of the total amount) and the elimination period lasted between 6 and 11 days for TC and 9 days for CTC, after treatment. Tetracycline use in laying hens is discussed, taking into consideration the proposals presented by the joint FAO/WHO Expert Committee on Food Additives.     

Studies on uptake and distribution of antibiotics in red cabbage

A large source of antibiotic active compounds and resistant bacteria is livestock waste, distributed as fertilizer on fields, used for vegetable cultivation. Frequently consumed vegetable, contaminated by low levels of antibiotics, may contribute to the development of bacterial antibiotic resistance. The objective of this work was to estimate the possible role of red cabbage as reservoir and carrier of antibiotic contaminants into the food chain. Red cabbage was exposed to antibiotics in hydroponic cultures and farming conditions. Enrofloxacin (ENR), chlortetracycline (CTC), monensin (MON) and amoxicillin (AMO) were separately added to nutrient solutions. Analysed by sequential extraction and LC–MS/MS methods, the plants revealed a remarkable uptake of CTC and in particular ENR (old leaves 0.22 mg/kg fresh weight (fw) CTC, 6.0 mg/kg fw ENR; roots up to 215.0 mg/kg fw CTC, 14.6 mg/kg fw ENR). The uptake of MON was significantly lower and AMO was not detectable. Red cabbage was also grown on manure-fertilized plots. The pig manure contained defined amounts of CTC and ENR (50 and 150 mg/kg). At harvest the edible parts of cabbage had between 9.2 to 16.9 µg/kg fw ENR, while there was no evidence obtained for the uptake of CTC. Finally, production steps of canned red cabbage were examined for carry over effects. Traces of tetracycline (16.4–19.2 µg/kg fw) were detected in supplies of freshly harvested vegetable, grown conventionally, but not in the marketable final product.