含氟无规两亲聚合物存在下含氟无皂乳液制备及表面性能研究

以含氟无规两亲聚合物(ASRF)为稳定剂,甲基丙烯酸六氟丁酯(FA)、苯乙烯等为单体,制备出含氟丙烯酸酯共聚物无皂乳液(PFAE)。研究了ASRF、FA用量对PFAE稳定性、乳胶膜吸水率和表面自由能的影响,并讨论了热处理对乳胶膜性能的影响。结果表明:适当增加ASRF和FA用量、提高处理温度,均有利于降低乳胶膜的吸水率和表面自由能;处理温度从30℃提高至110℃,吸水率可从31.49%降至12.08%,乳胶膜表面自由能下降幅度接近13.6%。ASRF和FA对PFAE稳定性均有一定影响。     

含氟丙烯酸酯共聚物表面施胶剂的制备及应用

以2-(N-甲基全氟辛烷基磺酰基)乙基丙烯酸酯(FM),丙烯酸丁酯(BA)、苯乙烯(St),甲基丙烯酸二甲胺乙酯(DM)为原料,采用无皂乳液聚合制得了阳离子含氟丙烯酸酯四元共聚物乳液.单独使用含氟乳液对纸张进行表面施胶,水和油滴在纸张上所成接触角最大可分别达到107.和93.,同时纸张的抗张强度、耐折度、白度分别提高12.46%、68.42%、0.66%.将淀粉和含氟乳液以不同质量比复配应用,讨论了复配体系对纸张防水防油性、强度、白度的影响.最后初步探讨了含氟乳液的施胶机理.     

含氟乳液纸张表面施胶剂的制备及应用研究

以全氟烷基乙基丙烯酸酯(FEA)、苯乙烯(St)、丙烯酸丁酯(BA)、甲基丙烯酰氧乙基三甲基氯化铵(DAC)为共聚单体,异丙醇为溶剂,偶氮二异丁脒盐酸盐(AIBA)为水溶性引发剂,采用半连续无皂乳液聚合法制备含氟丙烯酸酯无皂乳液。系统研究了该含氟乳液作为表面施胶剂对纸张性能的影响,并通过红外光谱进行了表征,通过接触角和扫描电子显微镜进行了性能测试。结果表明,当m(St)∶m(BA)∶m(FEA)∶m(DAC)=3∶3∶2∶1.2,乳液含氟量达到20%时,纸张的防水防油性较佳,抗张强度提高22.3%,耐折度提高38.2%。     

阳离子型含氟丙烯酸酯表面施胶剂的制备及应用

以甲基丙烯酸十二氟庚酯(FM)、丙烯酸丁酯(BA)、苯乙烯(St)、甲基丙烯酰氧乙基三甲基氯化铵(DMC)、丙烯酸十八酯(ODA)为原料,采用无皂乳液聚合制得了阳离子含氟丙烯酸酯多元共聚物乳液.单独使用含氟乳液对纸张进行表面施胶,水和油滴在纸张上所成的接触角最大可分别达到121°和80°;将淀粉和含氟乳液以不同质量比复配应用,讨论了复配体系对纸张防水防油性的影响.     

RAFT聚合诱导自组装法合成含氟聚丙烯酸酯无皂乳液

采用可逆加成-断裂链转移（RAFT）聚合合成的聚丙烯酸（PAA）为大分子RAFT试剂．通过聚合诱导自组装法合成了含氟聚丙烯酸酯无皂乳液。运用傅里叶红外光谱（FT—IR）、核磁共振氢谱（^1H—NMR）、透射电子显微镜（TEM）和动态光散射（DLS）对聚合物结构和乳胶粒进行了表征。结果表明：当NaOH用量为1．2％,PAA嵌段的聚合度为80时,乳液稳定性良好,转化率达95．1％,乳胶粒具有明显的核壳结构,粒径约为155nm。将含氟聚丙烯酸酯无皂乳液用于皮革涂饰后,随着丙烯酸六氟丁酯（HFBA）用量的增加,涂饰后的皮革对水接触角逐渐增加。当HFBA用量为6％时,涂饰后的皮革对水接触角为115．5°。     

微波辐射制备含氟乳液纸张施胶剂

用微波辐射乳液聚合的方法,合成甲基丙烯酸甲酯、丙烯酸丁酯与甲基丙烯酸六氟丁酯的三元含氟乳液纸张施胶剂,并通过表面涂布的方法对纸板进行施胶。探讨乳化剂用量、微波辐射时间和含氟单体用量对产率以及表面施胶纸板防水性能的影响。结果表明,微波功率为50 W的条件下,乳化剂用量为3%、含氟单体用量为10%、微波辐射时间为4.5 min时,产率能达到90%以上,当涂布量为0.9 g/m²时表面施胶纸板的接触角能达到121°,Cobb值能达到14 g/m²。     

非离子乳化剂对对C6防水剂稳定性和应用效果的影响

以非离子乳化剂对司盘60/吐温60和72/721分别与十八烷基三甲基氯化铵复配为复合乳化剂,研究其对C6防水剂乳液稳定性、乳液粒径、耐静水压和接触角、Zeta电位和防水防油应用效果的影响。非离子乳化剂对司盘60/吐温60和72/721的比例为1∶3时形成较强的正相互作用,可以降低乳液的凝胶率,减小乳胶粒粒径,增强乳液的机械稳定性以及稀释稳定性,乳液的防水防油性能较好。     

含氟丙烯酸酯乳液表面施胶剂的制备与应用

以甲基丙烯酸六氟丁酯(FMA)、醋酸乙烯酯(VAc)、丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)为单体,采用种子乳液聚合法制备了一种能够明显提高纸张施胶效果的含氟聚丙烯酸酯乳液。分析了FMA用量对该乳液的性能影响,测定了乳胶膜的对水接触角和吸水率。试验结果表明,用含氟聚丙烯酸酯乳液与淀粉复配进行表面施胶,当其施胶量为1.5g/m2时,可使纸张表面强度增强的同时大大提高纸张的施胶度。     

无皂苯丙乳液制备及表面施胶增强效果研究

以聚乙烯醇和丙酮为分散剂,苯乙烯、丙烯酸丁酯为单体,甲基丙烯酸缩水甘油酯为功能性单体,过硫酸钾为引发剂,采用无皂乳液聚合法合成无皂苯丙乳液.分析结果表明,无皂苯丙乳液胶粒粒径小且分布均匀、分散性好.用乳液浸渍处理纸张,不但具有施胶和增湿强效果,同时也能提高纸张的强度性能和印刷性能.将合成的无皂苯丙乳液与氧化淀粉复配对纸张性能改善的效果比单一使用氧化淀粉的效果好.施胶量较少时,无皂苯丙乳液与氧化淀粉复配不具有施胶和增湿强效果,但可改善纸张强度性能.     

水性含氟丙烯酸酯共聚物防水防油剂的研究

含氟化合物具有优异的防水防油性能,水性含氟丙烯酸酯共聚物聚合速度快、对环境污染小,乳状液产品可直接应用与生产中、制备和使用成本相对低,因而得到了迅速发展.该文介绍了水性含氟丙烯酸酯共聚物的制备方法,水性含氟丙烯酸酯共聚物作为纸张防水防油剂的作用机理和应用,并总结了有关纸张防水防油性的测定方法.     

新型松香石蜡阳离子中性施胶剂的制备及应用

以N-甲基吡咯烷酮(NMP)为助溶剂,苯乙烯(St)、丙烯酸十八酯(ODA)、甲基丙烯酰氧乙基三甲基氯化铵(DMC)、丙烯酰胺(AM)为单体,通过无皂乳液共聚反应合成了阳离子高分子乳化剂(CPE),并制备了阳离子松香石蜡乳液(CRPE).研究TCPF合成中St、ODA、DMC含量对CRPE稳定性能的影响;CRPE中松香、石蜡、CPE质量比对CRPE稳定性能以及施胶性能的影响;纸浆pH、CRPE用量及非离子聚丙烯酰胺用量对纸张施胶效果的影响.结果表明:W(St)=33%、w(ODA)=15%、w(DMC)=17%、m(松香):m(石蜡):m(CPE)=2:1:3时CRPE稳定性能较好,适宜的施胶条件为:采用逆向施胶工艺纸浆pH值为6,CRPE用量为1%,PAM用量为0.8%.     

苯乙烯-马来酸酐作分散剂的丙烯酸酯聚合物表面施胶剂的制备及应用

用溶液聚合法制备了苯乙烯-马来酸酐(SMA)共聚物,经氨水水解,得到水溶性高分子分散剂。以此作为高分子分散剂与苯乙烯(St)、丙烯酸(AA)、丙烯酸丁酯(BA)和丙烯酸羟乙酯(HEA)进行无皂乳液聚合制备出丙烯酸酯聚合物表面施胶剂。应用实验表明,单独使用进行表面施胶后的纸张有良好的抗水性能,施胶后的纸张施胶度可达120s,其抗张强度、耐破度、耐折度和环压强度分别可以提高21%、12.5%、26%和12.3%。     

水溶性壳聚糖接枝共聚物施胶剂的研究

以马来酸酐（MAH）改性后的水溶性壳聚糖（CS）为主链,苯乙烯（St）、丙烯酸丁酯（BA）和甲基丙烯酸甲酯（MMA）为单体,丙烯酸（AA）为功能单体利用核壳聚合技术制备了一种稳定的无皂乳液表面施胶剂。研究了反应条件的变化对马来酸酐改性壳聚糖、改性后壳聚糖接枝共聚物乳液的稳定性及乳液在纸张上施胶度的影响,确定了以下合成条件制得的水溶性壳聚糖的取代度最好：反应时间为4 h,反应温度为25℃,调节pH至10～11,m（MAH）：m（CS）=0.4。     

阳离子醚化改性聚乙烯醇干强剂的合成及应用

以聚乙烯醇(PVA)、苯乙烯(St)、丙烯酸丁酯(BA)、丙烯酰胺(AM)为基础单体,甲基丙烯酸羟丙酯(HPMA)为功能单体,甲基丙烯酰氧乙基三甲基氯化铵(DMC)为阳离子功能单体,2,3-环氧丙基三甲基氯化铵(GTMAC)为阳离子醚化剂,采用无皂乳液聚合法合成了阳离子醚化改性聚乙烯醇干强剂乳液;通过透射电镜(TEM)和扫描电镜(SEM)分别对干强剂乳液颗粒形态和纸张纤维形态进行表征和检测。结果表明,当HPMA用量为1.5%(对单体总质量而言,下同)时,干强剂乳液Zeta电位最大,体系较稳定;当GTMAC用量为1.5%时,纸张抗张强度的增幅为24.7%,耐折度的增幅为157%;当HPMA用量为1.5%～2.0%时,纸张的抗张强度和耐折度均较高。     

细乳液聚合制备含氟丙烯酸酯三元共聚物及性能表征

本工作以十二烷基硫酸钠（SDS）和脂肪醇聚氧乙烯醚（AEO-9）为乳化剂,采用细乳液聚合的方法,制备了甲基丙烯酸甲酯（MMA）、丙烯酸丁酯（BA）和全氟烷基丙烯酸酯（FA）三元共聚物。采用Fr—IR、^1H—NMR对聚合物的结构进行了表征;采用接触角法研究聚合物乳胶膜的表面性能。系统考察了超声均质强度（超声功率）、超声时间、FA用量、乳化剂用量等因素对细乳液聚合稳定性和乳液粒径及其分布的影响,优化的较佳细乳化工艺为：超声功率300W、超声时间3min、乳化剂用量为2．5％,FA单体质量分数〉4％;所制备的聚合物乳胶膜在低含氟量下即表现出优异的疏水疏油性能。     

阿魏酸对·OH诱导的肌原纤维蛋白氧化及凝胶特性的影响

为了探究阿魏酸（FA）对·OH诱导的肌原纤维蛋白（MPs）氧化及凝胶特性的影响,以猪肉肌原纤维蛋白为研究对象,利用Fenton氧化体系模拟实际肉品氧化环境,建立MPs-Fenton氧化体系,研究添加不同浓度水平（0、0.01、0.25、0.50 mg/g蛋白质）阿魏酸对猪肉MPs氧化及其凝胶特性的影响。结果表明:FA可以显著降低MPs羰基含量（P<0.05）,且抑制效果具有浓度依赖性,高浓度（0.50 mg/g）FA对羰基含量的抑制率高达38.2%;高浓度FA在氧化的基础上进一步促进MPs巯基损失,经·OH氧化体系氧化12 h后,其总巯基含量极显著降低了4.02%（P<0.01）。MPs氧化后溶解度降低,且随着FA添加浓度的增大,溶解度降低越明显,表明添加FA可以促进蛋白结构进一步展开,对MPs的氧化状态起到介导调控作用。氧化后的MPs凝胶强度显著降低（P<0.05）,凝胶弹性增强,当添加0.01 mg/g FA时弹性最强,之后随FA浓度的增加而降低,添加高浓度FA可使凝胶蒸煮损失增大,水分损失越多,保水性变差,氧化会导致MPs结构变化,形成较弱的凝胶网络结构。添加适量FA可以抑制MPs氧化及改善凝胶品质,高浓度的FA会影响蛋白成胶能力和凝胶品质。     

Dietary fatty acid and starch content and supplemental lysine supply affect energy and nitrogen utilization in lactating Jersey cows

The effects of dietary fatty acid (FA) and starch content as well as supplemental digestible Lys (sdLys) on production, energy utilization, and N utilization were evaluated. Each factor was fed at 5 different amounts, and factor limits were as follows: 3.0 to 6.2% of dry matter (DM) for FA; 20.2 to 31.3% of DM for starch, and 0 to 17.8 g/d of sdLys. Dietary FA and starch were increased by replacing soyhulls with supplemental fat and corn grain, respectively, and sdLys increased with rumen-protected Lys. Fifteen unique treatments were fed to 25 Jersey cows (mean ± SD; 80 ± 14 d in milk) across 3 blocks in a partially balanced incomplete block design. Each block consisted of 4 periods of 28 d, where the final 4 d were used to determine milk production and composition, feed intake, energy utilization (via total collection and headbox-style indirect calorimetry), and N utilization (via total collection). Response surface models were used to evaluate treatment responses. Increasing dietary FA decreased DM intake and milk protein yield. When dietary starch was less than 24%, milk protein concentration increased with increasing sdLys, but when dietary starch was greater than 26% milk protein concentration decreased with increasing sdLys. Digestibility of FA increased when dietary FA increased from 3.0 to 4.2% and decreased as FA increased beyond 4.2%. Although neutral detergent fiber digestibility decreased as dietary starch increased, energy digestibility increased. As dietary FA increased, metabolizable energy (ME) content quadratically increased. Supply of ME increased as dietary FA increased from 3.0 to 4.2% and decreased as FA increased beyond 4.2%. Increasing dietary FA and starch decreased CH₄ production and urinary energy. Increasing dietary starch increased the efficiency of utilizing dietary N for milk N. Increasing sdLys quadratically decreased N balance as sdLys increased from 0 to 8 g/d and increased N balance as sdLys increased from 8 to 18 g/d. Increasing dietary FA can increase ME content, however, at high dietary FA, decreased DM intake and FA digestibility resulted in a plateau in ME content and a decrease in ME supply. Our results demonstrate that sdLys supply is important for milk protein when dietary starch is low, and some Lys may be preferentially used for muscle protein synthesis at the expense of milk protein when sdLys is high.     

Effects of abomasal infusions of fatty acids and 1-carbon donors on apparent fatty acid digestibility and incorporation into milk fat in cows

Our primary objective was to determine the effects of the abomasal infusion of 16-carbon (16C) and 22-carbon (22C) fatty acids (FA) on apparent FA digestibility, plasma FA concentrations, and their incorporation into milk fat in cows. Our secondary objective was to study the effects of 1-carbon donors choline and l-serine on these variables. Five rumen-cannulated Holstein cows (214 ± 4.9 d in milk; 3.2 ± 1.1 parity) were enrolled in a 5 × 5 Latin square experiment with experimental periods lasting 6 d. Abomasal infusates consisted of (1) palmitic acid (PA; 98% 16:0 of total fat), (2) PA + choline chloride (PA+CC; 50 g/d of choline chloride), (3) PA + l-serine (PA+S; 170 g/d of l-serine), (4) behenic acid (BA; 92% 22:0 of total fat), and (5) docosahexaenoic acid algal oil (DHA; 47.5% DHA of total fat). Emulsions were formulated to provide 301 g/d of total FA and were balanced to provide a minimum of 40 and 19 g/d of 16:0 and glycerol, respectively, to match the content found in the infused algal oil. Apparent digestibility of FA was highest in DHA, intermediate in PA, and lowest in BA. Digestibility of 16C FA was lowest in BA and highest in PA. The digestibility of 22C FA was highest in DHA relative to BA (99 vs. 58%), whereas 1-carbon donors had no effect on 22C FA digestibility. Plasma 16C FA concentrations were greatest with PA treatment, and 22C FA concentrations were ~3-fold greater in DHA-treated cows relative to all other treatments. Milk fat 16:0 content was highest in PA relative to BA and DHA (e.g., 37 vs. 27% in PA and DHA), whereas the milk yield of 16:0 was higher in PA relative to DHA (i.e., 454 vs. 235 g/d). Similarly, milk 22:0 content and yield were ~10-fold higher in BA relative to all other treatments, whereas DHA treatment resulted in higher content and yield of 22:6 in milk fat relative to all other treatments (41- and 38-fold higher, respectively). Consequently, the content of FA >16C (i.e., preformed) was higher in milk fat from cows infused with BA and DHA relative to PA. De novo FA content in milk did not differ between PA, PA+CC, and PA+S (~16% of milk fat) but was higher in BA and DHA treatments (19 and 21%, respectively). We conclude that FA carbon chain length and degree of saturation affected FA digestibility and availability for absorption as well as their incorporation into milk fat. The abomasal infusion of choline chloride and l-serine did not modify these variables relative to infusing palmitic acid alone.     

Milk fatty acid composition of cows fed a total mixed ration or pasture plus concentrates replacing corn with fat

Thirty-one Holstein cows (six ruminally cannulated) were used to evaluate milk fatty acids (FA) composition and conjugated linoleic acid (CLA) content on three dietary treatments: 1) total mixed rations (TMR), 2) pasture (Avena sativa L.) plus 6.7 kg DM/d of corn-based concentrate (PCorn), and 3) pasture plus PCorn with 0.8 kg DM/d of Ca salts of unsaturated FA replacing 1.9 kg DM/d of corn (PFat). No differences were found in total (22.4 kg/d) or pasture (18.5 kg/d) dry matter intake, ruminal pH, or total volatile fatty acids concentrations. Fat supplementation did not affect pasture neutral detergent fiber digestion. Milk production did not differ among treatments (19.9 kg/d) but 4% fat-corrected milk was lower for cows fed the PFat compared to cows fed the TMR (16.1 vs. 19.5 kg/d) primarily because of the lower milk fat percentage (2.56 vs. 3.91%). Milk protein concentration was higher for cows fed the TMR than those on both pasture treatments (3.70 vs. 3.45%). Milk from the cows fed the PCorn had a lower content of short- (11.9 vs. 10.4 g/100 g) and medium-chain (56.5 vs. 47.6 g/100 g) FA, and a higher C18:3 percentage (0.07 vs. 0.57 g/100 g) compared with TMR-fed. Cows fed the PFat had the lowest content of short- (8.85 g/100 g) and medium-chain (41.0 g/100 g) FA, and the highest of long-chain FA (51.4 g/100 g). The CLA content was higher for cows in PCorn treatment (1.12 g/100 g FA) compared with cows fed the TMR (0.41 g/100 g FA), whereas the cows fed the PFat had the highest content (1.91 g/100 g FA). Pasture-based diets increased the concentrations of long-chain unsaturated FA and CLA in milk fat. The partial replacement of corn grain by Ca salts of unsaturated FA in grazing cows accentuated these changes. However, those changes in milk FA composition were related to a depression in milk fat.     

Feeding soybean oil to dairy goats increases conjugated linoleic acid in milk

A total of 24 Murciano-Granadina dairy goats milked once daily throughout lactation were used to study the effects of including soybean oil (SBO) in the diet on lactational performance and milk fatty acid (FA) content, particularly conjugated linoleic acid (CLA) and trans-vaccenic acid (trans-11 C18:1, TVA). Three weeks after parturition, goats were allocated to 2 balanced groups according to lactation number, body weight, and daily milk yield, and were kept in separate pens. The experiment consisted of a 2-period (28 d each) crossover with 2 dietary treatments: control and SBO (6% as fed in the concentrate). Goats were fed dehydrated fescue (ad libitum), alfalfa pellets (0.5 kg/d), and concentrate (1 kg/d) to which the SBO was or was not added. Forage was fed in the pens, and concentrate was fed individually in 2 equal portions at milking (0900 h) and in the afternoon (1700 h). Final SBO content in the consumed SBO diet was 2.5% (dry matter basis). Diets were isonitrogenous (17.4% crude protein), but their total FA content varied from 2.2% (control) to 4.6% (SBO). There was no effect of SBO on dry matter intake, milk yield, energy-corrected milk, body weight, or body condition score. Compared with the control diet, feeding SBO increased milk fat content (4.57 vs. 5.24%) and yield as well as total solids content. Soybean oil had no effect on milk crude and true protein contents, but it reduced milk casein content (2.48 vs. 2.34%). Short- and medium-chain FA decreased by feeding SBO, whereas long-chain FA increased. Feeding preformed linoleic acid through SBO increased milk concentrations of linoleic, oleic, and stearic FA but reduced levels of linolenic and palmitic FA. As a consequence, feeding SBO decreased the saturated-to-unsaturated FA ratio and the atherogenicity index. Compared with the control treatment, milk contents of cis-9, trans-11 CLA (0.68 vs. 2.03%) and TVA (2.04 vs. 6.41%) in the SBO treatment increased by approximately 200%. In conclusion, feeding a moderate dose of SBO to dairy goats was a useful way to increase milk fat, CLA, and TVA contents in milk and to reduce the atherogenicity index without negative effects on intake, milk yield, and protein content.