脂肪烃改性水基聚氨酯分散体的研究

采用硬脂酸单甘酯(GM)、异佛尔酮二异氰酸酯(IPDI)、聚醚(PE220)和二羟甲基丙酸(DMPA)为主要原料,合成了水基聚氨酯分散体,研究了硬脂酸单甘酯添加量对相同羧基含量下,聚氨酯水分散体粒径大小、分散体稳定性及涂膜性能的影响,并应用傅立叶红外光谱仪(FT-IR)测定反应产物的结构,应用激光纳米粒度仪,研究分散体乳液稳定性随着时间变化的关系。研究表明:硬脂酸单甘酯的引入,能够提高水基聚氨酯涂膜的物理机械性能和耐水性,当硬脂酸单甘酯添加量为5%、NCO/OH摩尔比为1.5∶1、羧基含量的质量分数在1.50%时,可得到固体质量分数为35%、贮存期在12个月以上的稳定性水基聚氨酯分散体,制得的水基聚氨酯涂料,具有较好的成膜性、柔软性和良好的耐水性。     

水性聚氨酯改性明胶皮革涂饰剂的制备与表征

合成了一种水性聚氨酯预聚体,并于水性介质中在偶联剂的作用下将聚氨酯接枝于明胶链上,制备出一种新型皮革涂饰剂。该研究对水性聚氨酯预聚体的合成中预聚温度,二羟甲基丙酸用量(DMPA)及三乙胺(TEA)用量的研究结果表明:最适预聚温度为65℃,最佳DMPA用量为4%,最宜中和度为85%;FT-IR光谱分析表明:明胶链上的—NH2,—OH参与了偶联反应;物理机械性能测试结果表明:当明胶和聚氨酯的质量比为50∶50时,改性胶膜的断裂伸长率可达325.6%,抗张强度为37.3MPa,透湿量为347%,溶剂吸收率为26.8%,吸水率为65%。应用性能测试表明:在明胶和聚氨酯的质量比为50∶50时,所涂皮块的耐干擦等级为5,耐湿擦等级为4。     

扩链剂对脂肪族水性聚氨酯性能的影响

以异佛尔酮二异氰酸酯(IPDI)和聚醚二醇(PPG∶M_n=1000)为原料进行预聚反应,二羟甲基丙酸(DMPA)为亲水扩链剂,按不同配比合成了水性聚氨酯,并就DMPA用量、乙二胺(EDA)扩链方式对水性聚氨酯乳液的稳定性、粒径、及其材料的力学性能、吸水率等的影响进行了研究。结果表明:DMPA用量6%左右,EDA溶于水中进行边扩链、边乳化的方法制得了综合性能较好的水性聚氨酯。     

水性聚氨酯分散体的改性探讨

详细讨论了水性聚氨酯分散体 (PUD)改性研究的新进展 ,如交联、利用有机硅氧烷以及丙烯酸树脂改性PUD等。同时对利用纳米材料、纳米技术改性PUD也作了初步探讨和设想。最后指出了水性聚氨酯分散体的发展趋势为高性能、多功能复合型     

二醋酸纤维素改性水性聚氨酯的制备及薄膜性能

以异佛尔酮二异氰酸酯(IPDI)、聚醚2000(PPG2000)作为主要原料,二醋酸纤维素(CDA)为改性剂,制备了一系列CDA改性的水性聚氨酯(WPU)。研究了CDA用量对改性前后WPU薄膜的热稳定、耐水性、涂层附着力和硬度的影响。结果表明,CDA的加入改善了WPU的热稳定性、耐水性、耐溶剂性及附着力,尤其是薄膜硬度显著提高。当CDA用量为6.8%质量分数时,薄膜的综合性能较好。红外光谱(FT-IR)表征发现WPU分子骨架上成功引入了CDA,热重(TG)分析表明CDA改性后WPU薄膜热稳定性得到提高。     

阴离子型水性聚氨酯-丙烯酸酯复合乳液的合成与性能研究

采用无皂乳液聚合的方法,制备出了具有核壳结构的水性聚氨酯-丙烯酸酯复合乳液(PUA)。通过对乳液的黏度、粒径、涂膜的耐水性、机械性能和热性能等的测定,讨论了阴离子水性聚氨酯的用量对PUA乳液和涂膜性能的影响。结果显示:在水性聚氨酯用量为50%时,随着水性聚氨酯用量的增加,乳液的粒径逐渐下降、表观黏度上升;PUA乳液涂膜的耐水性、机械性能和热稳定性以及附着力、抗冲击强度、硬度和柔韧性较好。     

新型光固化水性涂料应用于杨木胶合板涂饰工艺的优化

以杨木胶合板为基材,采用水性UV涂料进行表面涂饰,参照色漆和清漆涂膜性能的标准,分析胶合板表面特性、预干燥环境、紫外光辐射时间对涂膜质量的影响。结果表明:当基材含水率8%,表面粗糙度为3.36,水性UV涂料湿膜厚度30μm,预干燥温度50℃,预干燥时间43min,紫外光辐射时间20s时,水性UV涂料涂膜质量最好,此时涂膜铅笔硬度达到2H,光泽度达到199.4,附着力等级为0级,耐磨性和抗冲击性最佳。     

胍胶改性水性聚氨酯的合成及性能研究

通过预聚体合成法,以胍胶为内交联剂、二羟甲基丙酸为亲水扩链剂,合成了胍胶改性水性聚氨酯(GWPU)。采用傅里叶变换红外光谱(FT-IR)、透射电子显微镜(TEM)、动态光散射(DLS)、热重分析法(TGA)等对GWPU进行表征,考察了胍胶用量对GWPU乳液粒径和外观以及胶膜机械性能的影响。研究结果表明:胍胶成功引入到聚氨酯分子链上,当胍胶用量为0.3%时,乳液稳定性好,粒子呈球形,粒径较小且分布均匀,拉伸强度为25.83MPa,硬度为89.35HA。胍胶不仅改善了水性聚氨酯的耐热性能,而且明显提高了胶膜的机械性能。与水性聚氨酯相比,胍胶改性水性聚氨酯涂饰革样的拉伸强度较高。     

纳米二氧化钛对木器硝基涂料性能的影响研究

采用纳米TiO_2对硝基涂料进行改性,并对改性后的木器硝基涂料涂层的力学性能(耐磨性、硬度、附着力和抗冲击性能)和光学性能进行测试,探究纳米TiO_2对涂膜的力学性能与光学性能的影响。结果表明:实验中纳米TiO_2添加量的不同对涂膜硬度和附着力没有产生显著影响,添加量为0.1 g时涂膜耐磨性较好并处于亚光状态,此时纳米TiO_2与涂料的质量比为1:30。当进一步使用0.01 g烷基烯酮二聚体对0.1 g纳米TiO_2进行表面修饰后,得到的涂膜性能达到最佳,此时涂膜硬度为HB、附着力为1级、磨耗值为0.024 g、光泽度为19%。该研究丰富了无机纳米粒子(TiO_2)改性硝基涂料的应用范围。     

马来酸酐改性HTPB-PU型乳液合成及其膜性能检测

以聚醚210、端羟基聚丁二烯(HTPB)、4,4′-二环己基甲烷二异氰酸酯(H-MDI)、二羟甲基丁酸(DMBA)和三羟甲基丙烷(TMP)为原料,合成HTPB-PU预聚体。通过自由基聚合反应将马来酸酐(MAH)接枝到HTPB-PU上,制备MAH改性的HTPB-PU乳液。研究了MAH用量对HTPB-PU性能的影响。通过傅立叶变换红外光谱仪(FT-IR)、纳米粒度仪、热失重分析(TGA)等方法,对马来酸酐改性的HTPB-PU结构及胶膜热稳定性进行分析。同时,探究了马来酸酐用量对水性聚氨酯乳液稳定性、粒径和胶膜吸水性、力学性能、耐酸稳定性的影响。结果表明:随着MAH用量的增加,乳液粒径增大,胶膜的热稳定性有所提高、耐溶剂性增强;质量分数为8.13%的MAH能够使胶膜的吸水率由58.6%降低到29.8%,且胶膜的抗张强度最佳。     

Manufacture of acid gels from skim milk using high-pressure homogenization

The effect of high-pressure homogenization (HPH) alone or in combination with a thermal treatment (TT) was investigated for the manufacture of acid gels from skim milk. Raw skim milk was subjected to HPH (0 to 350 MPa) or a TT (90°C, 5 min), or both, in the following processing combinations: 1) HPH, 2) HPH followed by TT, 3) TT followed by HPH, 4) TT, and 5) raw milk (control). After treatments, L* (lightness) values were measured, and then skim milk was acidified with 3% glucono-δ-lactone and rheological properties (G′ and gelation time), and whey holding capacity was evaluated. Treatments in which HPH and TT were combined showed greater L* values than those in which just HPH was applied. In all treatments, the L* values decreased as the pressure was increased up to 300 MPa with little change afterward. Gelation times were lower when HPH was combined with TT compared with the acid skim milk gels that were just pressure treated. The final G′ in gels obtained from skim milk subjected to the combined process (HPH and TT) was greater and pressure-dependent compared with all other gels. A maximum G′ (∼320 Pa) was observed with skim milk subjected to a combination of thermal processing before or after HPH at 350 MPa. Acid gels obtained from HPH milk at 350 MPa showed a linear decrease in whey holding capacity over time, retaining 20% more whey after centrifugation for 25 min compared with samples treated at lower pressures and all other treatments. Our results suggest that HPH in combination with TT can be used to improve the rheological properties and stability of yogurt, thus decreasing the need for additives.     

Physical assessment of composite biodegradable films manufactured using whey protein isolate,gelatin and sodium alginate

Composite films were manufactured using whey protein isolate (WPI), gelatin (G) and sodium alginate (SA) using a simplex centroid design. Tensile strength (TS), puncture strength (PT), percentage elongation at break point (E), tear strength (TT), water vapour permeability (WVP) and oxygen permeability (OP) of films were evaluated. The interactions between biopolymers showed quadratic effects (P < 0.01) on TS, E, PT, TT and WVP values. Scanning electron microscopy (SEM) was performed to investigate the microstructures of composite films. The proportion of ingredients required to produce the optimum composite films was determined to be: WPI (g):G (g):SA (g) = 8.0:12.0:5.0. Overall, films (WPIGSA-9) produced using the combination of WPI (g):G (g):SA (g) = 10.0:16.0:14.0 demonstrated the best barrier to oxygen (8.00 cm³ μm/m² d kPa); while films (WPIGSA-1) showed the best barrier to water vapour (48.04 g mm/kPa d m²); films (WPIGSA-6) using the combination of WPI (g):G (g):SA (g) = 10.0:17.5:22.5 had the best mechanical properties of all of the experimental composite films tested.     

壳聚糖/明胶食品保鲜复合膜的热稳定性研究

采用溶液共混法制备壳聚糖/明胶复合膜,测定复合膜的透光率及水溶性,并用热重分析法系统研究了复合膜的热降解性能。结果表明,随着明胶含量的增加,复合膜的透光率上升,水溶性增强,热稳定性提高。热分析结果显示,复合膜在氮气中的热降解为两步反应,降解温度（T）随着明胶含量（X）的增加而升高,起始降解温度To=0.03467X+246.5,最大速率降解温度Tp=0.3460X+282.1,终止降解温度Tf=1.001X+311.9;对应于Tp的降解率Cp不受X的影响,平均值为35.32%±2.54%,对应于Tf的降解率Cf也不受X的影响,平均值为56.28%±1.56%;复合膜热降解反应的活化能（E）和频率因子（A）随反应程度的增加而改变,分三个过程。      

热处理温度对明胶-魔芋粉复合膜性质的影响

为考察热处理温度对明胶-魔芋粉复合膜理化性质的影响,测定和比较了复合膜的溶解性、接触角、微观结构和热稳定性等指标。结果发现,未经热处理的复合膜在30?℃温水中的膜溶解率（film solubility,FS）和蛋白溶解率（protein solubility,PS）分别为45.62%和28.83%,而在90?℃热水中分别为74.32%和71.44%。当复合膜经热处理后,膜的FS和PS随着热处理温度的升高逐渐下降。30?℃温水中溶出的α和β链蛋白条带浓度随热处理温度升高逐渐降低,而90?℃热水中溶出的蛋白受热处理温度影响不明显。复合膜明胶侧的接触角为107.14°,而魔芋粉侧的接触角为88.53°,经过热处理后均出现上升的趋势。伴随热处理温度的升高,膜的水蒸气透过率出现一定程度的下降,而b*值和透明度均出现上升的趋势。根据扫描电子显微镜分析和差示扫描量热法检测的结果,可以发现随热处理温度的升高,复合膜的明胶层和魔芋粉层逐渐融合在一起,而且膜的热稳定性逐渐上升。以上结果表明,提高热处理温度可以改善明胶-魔芋粉复合膜的耐水性、表面疏水性、阻水性和热稳定性。     

Effect of Incorporation Nanocrystalline Corn Straw Cellulose and Polyethylene Glycol on Properties of Biodegradable Films

This work aimed to study the effect of nanocrystalline corn straw cellulose (NCSC) and polyethylene glycol (PEG) on the properties of biodegradable corn distarch phosphate (CDP) films. The mechanical properties and barrier properties were investigated. Meanwhile, the compatibility, crystallization, thermal stability, and morphological structure of the films were characterized by Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (X‐RD), thermogravimetric (TGA), and scanning electron microscopy (SEM). In contrast with the CDP films, incorporation of NCSC in the films improved their tensile strength (TS) significantly, and incorporation of PEG improved their elongation at break (EAB) significantly else. PEG, CDP, and NCSC (P‐CDP/NCSC) blend films had the best barrier properties. The thermal stability of the films was increased by the incorporation of NCSC. X‐RD showed that CDP and NCSC (CDP/NCSC) films had higher crystallinity. SEM revealed that all films had smooth surface, while the films presented a uniform network structure through the incorporation of NCSC.     

大豆分离蛋白膜的DSC分析

采用差示扫描量热法(DSC),研究不同相对湿度(RH)条件下,大豆分离蛋白(SPI)膜的热特性以及谷氨酰胺转移酶(TGase)改性对热特性的影响。对于SPI膜,无论是对照膜还是TGase改性膜,蛋白膜的热稳定性随着RH的增高而下降。TGase改性改变了SPI膜吸热峰出现的位置与数量。在同一RH条件下,TGase改性膜更易失去水分。TGase改性使SPI膜的耐热特性基本未变。     

甘油对大豆分离蛋白/海藻酸钠复合膜热分解的影响

本文采用流延法制备了一系列甘油增塑、与海藻酸钠共混改性的大豆分离蛋白/海藻酸钠复合膜,并利用热重分析方法对这些复合膜的热分解性能进行了考察.热分解实验中,通过改变升温速率,研究甘油含量对大豆分离蛋白/海藻酸钠复合膜热分解性能的影响.从所得到的TGA和DTA曲线可知,大豆分离蛋白/海藻酸钠复合膜的热分解行为可以分为三个较明显的降解阶段.根据失重速率的变化确定热分解反应最剧烈的温度区间为420 ～630K,对此采用Coats-Redfern方法进行了热分解动力学分析,并得出该阶段为一级热分解反应的结论.通过动力学模型,可以计算得到这些复合膜热分解反应的动力学参数,如表观活化能和指前因子.实验结果显示,甘油的加入使复合膜更易热分解;计算也表明热分解活化能随着甘油量的增加而不断下降,降幅可达50％.     

桔子精油优化鱼鳞明胶膜性能的作用研究

为改善鱼鳞明胶膜的性能,测定添加明胶质量的0%、25%、50%、75%、100%桔子精油的可食膜的厚度、机械性能、水溶性、水蒸汽透过率、色泽、透明度和透光率、热性能、红外光谱和抑菌活性。结果表明:随着精油浓度的增加,鱼鳞明胶膜的厚度、断裂伸长率增加,拉伸强度、透光率、水溶性降低,水蒸汽透过率呈现先增加后降低的趋势;差示扫描量热法(DSC)和傅里叶变换红外光谱(FTIR)分析结果表明,鱼鳞明胶分子与桔子精油的部分成分发生相互作用,在一定程度上改善了明胶膜的热稳定性;桔子精油的添加还赋予了鱼鳞明胶膜抑菌作用。综合评价得出75%质量浓度的桔子精油添加量对鱼鳞明胶膜各项性能优化效果最好,本实验结果可为生产高性能的鱼鳞明胶膜提供理论基础。     

Properties of cast films of vicilin-rich protein isolates from Phaseolus legumes: Influence of heat curing

The mechanical, hydrophobic and thermal properties of cast films of vicilin-rich protein isolates from three Phaseolus legumes were investigated and compared to that of soy protein isolate (SPI). The influence of heat curing at 85 °C on the properties of these films was characterized. The films of vicilin-rich protein isolates exhibited much less mechanical strength (TS) and elongation at break (EB) and similar film surface hydrophobicity, as compared with those of the SPI film. The heating remarkably improved the TS of these films, and the extent of the improvement much higher than that of the SPI film, while the EB was only slightly affected. The thermal properties of these protein isolate films were variable, and much distinctly affected by the heating of the films, to a various extent, depending on the type of protein isolates. Protein solubility analyses indicated strengthened hydrogen and hydrophobic bondings of these films by the heating. The results suggest that those vicilin-rich protein isolates have good potential to form cast films with mechanical strength comparable to that of SPI film.     

Structure and mechanical properties of sodium and calcium caseinate edible active films with carvacrol

Edible active films based on sodium caseinate (SC) and calcium caseinate (CC) plasticized with glycerol (G) at three different concentrations and carvacrol (CRV) as active agent were prepared by solvent casting. Transparent films were obtained and their surfaces were analysed by optical microscopy and scanning electron microscopy (SEM). The influence of the addition of three different plasticizer concentrations was studied by determining tensile properties, while Fourier transformed infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were used to evaluate the structural and thermal behavior of such films. The addition of glycerol resulted in a reduction in the elastic modulus and tensile strength, while some increase in the elongation at break was observed. In general terms, SC films showed flexibility higher than the corresponding CC counterparts. In addition, the presence of carvacrol caused further improvements in ductile properties suggesting the presence of stronger interactions between the protein matrix and glycerol, as it was also observed in thermal degradation studies. FTIR spectra of all films showed the characteristic bands and peaks corresponding to proteins as well as to primary and secondary alcohols. In summary, the best results regarding mechanical and structural properties for caseinates-based films containing carvacrol were found for the formulations with high glycerol concentrations.