Synthesis and Processing of Graft Copolymers Prepared from Cereal Flour and Methyl Acrylate

Ceric-initiated graft polymerizations of methyl acrylate onto corn and wheat flour were carried out in a 2-gallon reactor to provide pound quantities of these polymers for characterization and processing. Conversions of monomer to poly(methyl acrylate) (PMA) were nearly quantitative, although considerable homopolymer was formed along with grafted PMA. The resulting polymers were extrusion processed into plastic ribbons, and films were also prepared from these polymers by extrusion blowing. Tensile properties of the products were determined. Comparison of the preparation and properties of PMA-grafted flour with our earlier research on starch-g-PMA revealed some important differences between the two polymerization systems. Graft polymerizations onto flour required a higher concentration of ceric initiator to give a near quantitative conversion of monomer to polymer and yielded a higher percentage of ungrafted homopolymer. Also, extruded ribbons obtained from PMA-grafted flour generally exhibited lower UTS, higher % elongation and higher tear strength than extrudates prepared from PMA-grafted starch. In contrast to our findings with PMA-grafted starch, flour-g-PMA could be processed into continuous extrusion films, even though flour was graft polymerized in the granular state and was not dissolved/dispersed in water prior to graft polymerization. The percent shrinkage of extrusion blown flour-g-PMA at room temperature and 100% relative humidity was less than that observed for analogous starch-based films.     

Synthesis and Properties of Polyacrylamide-Starch Graft Copolymers

Graft polymerization of acrylamide onto rice starch was investigated under different conditions using potassium persulphate, benzoyl peroxide or potassium permanganate as initiator. This has led to establishment of the most appropriate grafting conditions for each of these initiators. Under these conditions grafting was characterized by two rates regardless of the initiator used. The first rate occurred during the initial stages of polymerization while the second during the later stages. The first rates of grafting for the three initiators were very close indicating the insignificant effect of the nature of the initiator on grafting during the initial stages of the reaction. On the other hand, the second rates of grafting exhibited the order: potassium persulphate < benzoyl peroxide < potassium permanganate, reflecting the role played by the nature of initiator during the later stages of the reaction. Substantial differences in solubility were observed between polyacrylamide-starch graft copolymers and unmodified starch as well as among copolymers prepared using the three initiators. Although the copolymers acquired higher solubility percent than the unmodified starch, yet nature of initiator, graft yield, structural changes in the copolymer occuring during grafting and the temperature of solubility measurement determined the solubility percent. Copolymers prepared using benzoyl peroxide or potassium persulphate showed lower viscosity than the unmodified starch. The opposite was the case with respect to copolymer prepared using potassium permanganate.     

丙烯酸甲酯与竹原纤维的接枝共聚及表征

以Ce^4＋为引发剂,研究了丙烯酸甲酯（MA）与竹原纤维的非均相接枝共聚反应。分析了单体浓度、Ce^4＋浓度、介质酸度、反应时间和温度对接枝率的影响,确定了最佳接枝反应条件。结果表明：[MA]=0．18mol／L,[Ce^4＋]=O．01mol／L,[Hq=0．07mol／L,时间3-4h,温度为40℃时,接枝率较高。并用ATR、SEM、XRD和TG对接枝纤维进行了表征,接枝后纤维结晶度下降,热稳定性能提高。     

玉米淀粉加工结晶葡萄糖研究综述

本文综述了国内外淀粉加工结晶葡萄糖液化、糖化的方法以及葡萄糖结晶的方法，分析了液化、糖化及结晶存在的问题，指出了今后研究的重点。     

菜籽油接枝聚合物加脂剂的制备与性能研究

本文通过考察反应温度、反应时间和引发剂用量对产物水接触角和黏度的影响,探索了菜籽油与丙烯酸单体发生聚合反应的反应条件.通过红外谱图分析,证明聚合反应已经实现.     

菜籽油接枝聚合物加脂剂的制备与性能研究

本文通过考察反应温度、反应时间和引发剂用量对产物水接触角和黏度的影响,探索了菜籽油与丙烯酸单体发生聚合反应的反应条件。通过红外谱图分析,证明聚合反应已经实现。     

Synthesis of Poly(Methacrylic Acid-)Starch Graft Copolymers Using Mn-IV-Acid System

When starch was treated with KMnO₄ solution, MnO₂ was deposited overall the starch. The amount of MnO₂ deposited relied on the KMnO₄ concentration. Subjecting the MnO₂-containing starch to a solution consisting of monomer (methacrylic acid, MAA) and acid (citric, tartaric, oxalic or sulphuric acid) resulted in formation of poly(MAA)-starch graft copolymer. The magnitude of grafting, expressed as meq. -COOH/100 g starch, was determined by amount of MnO₂ deposited, MAA concentration, temperature and duration of polymerization as well as kind and concentration of the acid. Incorporation of cations such as Fe⁺³, Cu⁺² and Li⁺¹ had a significant effect on grafting. The highest extent and rate of grafting were obtained with citric acid and the least with sulphuric acid; tartaric acid stood in-mid-way position. The magnitude of grafting increased as the acid concentration increased till a certain concentration beyond which grafting levelled off. Similar trend was observed when the magnitude of grafting was related to the amount of MnO₂ deposited. The extent and rate of grafting increased by raising the polymerization temperature from 30° to 50°C then decreased by raising the temperature further from 60° to 70°C. On the other hand, grafting enhanced significantly by addition of Fe⁺³, Cu⁺² or Li⁺¹ and followed the order Fe⁺³ > Cu⁺² > Li⁺¹. A tentative mechanism for grafting of starch with MAA using MnO₂-acid system was elucidated.     

Extrudates of Cornstarch with Urea and Glycols: Structure/Mechanical Property Relations

Urea, various glycols and mixtures of these were tested as plasticizers for gelatinized cornstarch. Mixtures of cornstarch, urea and/or triethylene glycol, glycerol or propylene glycol were extruded into ribbons. Mechanical and structural properties of the ribbons were evaluated by tensile testing, DSC and NMR. Flexible ribbons were obtained only when enough urea or glycol was present to lower the glass transition temperature of the starch near or below room temperature. Ribbons containing high levels of urea were rather stiff, reflecting the low mobility of urea. Ribbons containing high levels of glycol were, in contrast, soft and weak. Samples extruded with mixtures of urea and glycols exhibited enhanced elongations at break. All samples became brittle at very low humidities and soft at high humidities.     

聚丙烯工程纤维物理力学性能探讨

为探讨聚丙烯纤维的物理力学性能,对实验室2005～2008年四年时间内检测的近200个聚丙烯纤维样品物理指标进行分析,并与国家标准GB/T21120—2007《水泥混凝土和砂浆用合成纤维》和行业标准JT/T525—2004《公路水泥混凝土纤维材料聚丙烯纤维和聚丙烯氰纤维》比较,发现我国聚丙烯工程纤维的物理力学性能基本满足各自企业标准要求,达到甚至超过国家标准和行业标准的规定。     

Graft Copolymers of Starch and Polyacrylonitrile. Effect of Source

Graft copolymers of tuber and legume starches with polyacrylonitrile (PAN) have been prepared. Molecular weight, frequency of grafting, and adsorbencies of saponified products have been investigated. Yield and add-on of granular graft copolymers are dependent on the source of starch. Parameters for gelatinized graft copolymers are almost constant. Yield, add-on, molecular weight and adsorbencies are different for the granular graft copolymer of garden pea starch. On pretreatment up to 70°C, these parameters are comparable with those of other starch graft copolymers.     

再生纤维素纤维的物理机械性能对比

对竹浆纤维、Modal、Tencel与粘胶纤维 4种再生纤维素纤维的物理机械性能进行探讨 ,以利于更好地认识和利用这 4种纤维及其织物。     

Characterization and Multivariate Analysis of Physical Properties of Processing Peaches

Characterization of physical properties of fruits represents the first vital step to ensure optimal performance of fruit processing operations and is also a prerequisite in the development of new processing equipment. In this study, physical properties of engineering significance to processing of three popular cultivars of clingstone peaches were evaluated, including dimensional parameters, mass, dimensional ratios, aspect ratio, elongation index, sphericity, bulk density, texture, color, and flavor. Based on these physical properties, multivariate analysis of variance (MANOVA), canonical variate analysis (CVA), principal component analysis (PCA), and partial least squares and linear discriminate analysis (PLS-LDA) were applied to qualitatively and quantitatively discriminate the cultivar difference. Results showed that the studied peach cultivars had significantly different (p?<?0.05) geometric characteristics. The peaches can be classified based on the cheek diameter (D_c) into three different size categories, including small- (D_c less than 60 mm), medium- (D_c between 60 mm and 70 mm), and large- (D_c higher than 70 mm) sized peaches. The peach flesh firmness significantly (p?<?0.05) decreased with the increase of peach size, while the pit dimensions were independent of peach size. There were no apparent distinctions in color characteristics, bulk density, and sugar content among the three cultivars. The measurements and quantitative discrimination of peach properties in this study would benefit equipment design and process innovation to enhance the processing efficiency and quality of processed peaches.     

快速崩解羧甲基-交联玉米淀粉性能研究及结构表征

以玉米淀粉为原料,采用交联、醚化复合变性方法,将溶剂法与微波固相法工艺结合成功的制备了药用快速崩解剂羧甲基-交联玉米淀粉(CCMS).红外光谱仪检测显示淀粉分子上引进了羧基基团,产物为目标产物;扫描电子显微镜(SEM)检测结果显示羧甲基-交联玉米淀粉的颗粒较原淀粉粗糙,颗粒表面有小孔洞;偏光显微镜观察显示羧甲基-交联玉米淀粉的偏光十字强度较原淀粉弱,表明其晶体结构已遭到部分破坏;热分析(TGA-DTA)表明CCMS的耐热性较原淀粉、CMS差,但其热稳定性比原淀粉、CMS高.DSC分析显示,CMS和CCMS与玉米原淀粉相比,糊化温度降低;X-衍射分析显示CCMS的晶体结构受到明显破坏,而CMS的X-射线衍射强度也有减弱,表明改性不仅发生在淀粉结构的无定型区,也发生在结晶区.本试验所得的产品在常温下能快速吸水膨胀,促药片崩解性能好.     

丙烯酸甲酯和二乙醇胺的反应动力学研究

对丙烯酸甲酯和二乙醇胺的反应动力学进行了研究.通过React IR IC10在线红外光谱仪实时跟踪丙烯酸甲酯在1640 cm-1处特征吸收峰强度的变化,确定合成N,N-二羟乙基-3-胺基丙酸甲酯反应的最佳反应时间为2h,反应级数为二级,反应的表观活化能为36.9588 kJ/mol.     

淀粉/MMA-EA自交联型接枝共聚物的合成与结构表征

在联联剂存在下,以硝酸铵为引发剂研究了玉米淀粉与甲基丙烯酸甲酯和丙烯酸乙酯进行自交联接枝共聚合成反应的规律,讨论了引发剂浓度、单体浓度、反应温度和反应时间对接枝共聚反应的影响。实验结果表明,在引发剂浓度为７．０＊１０＾－３ｍｏｌ／ｌ、单体浓度为１．３０ｍｏｌ／ｌ、反应温度为５１℃、反应时间为２．５小时,自交联接枝共聚物的接枝率较高。通过红外光谱和Ｘ－射线粉末衍射对共聚物进行了结构表征。     

黄油的加工方法及其物理性质和营养成分

介绍了黄油的加工方法及加工中允许使用的食品添加剂,从成分、色泽、组织状态、风味等方面介绍了黄油的物理性质,并初步评价了黄油的营养价值,对黄油的生产者和消费者具有一定的参考价值。     

过硫酸钾引发淀粉与丙烯酸丁酯的接枝共聚

淀粉与丙烯酸丁酯接枝共聚,生成变性淀粉,可使用许多种引发剂。文章采用价廉的过硫酸钾为引发剂,通过试验讨论了单体浓度、引发剂浓度、反应温度以及时间对接枝率和接枝效率的影响。     

生丝冷冻对其机械物理性能的影响

本文通过生丝吸湿、低湿冷冻处理后测定生丝的机械物理性能，发现生丝冷冻对其机械物理性能有明显影响，并与冷冻前生丝的回潮率关系密切。生丝经冷冻处理后其强力，抱合力成绩随着回潮率的增加而下降，而生丝的伸长率和直径则无明显变化。