微晶纤维素改性对聚乙烯醇薄膜性能的影响

目的研究不同添加量的微晶纤维素(MCC)对聚乙烯醇(PVA)薄膜性能的影响。方法通过共混溶液流延法制备得到MCC质量分数不同(0%,1%,2%,3%,4%)的PVA薄膜,测定分析MCC含量不同对PVA薄膜的颜色、光学性能、力学性能、阻隔性能、热稳定性和表面微观形态的影响。结果随着MCC含量的增加,PVA薄膜的透光率和断裂伸长率显著降低,雾度和抗拉强度显著增加,与纯PVA薄膜相比,MCC质量分数为4%的PVA薄膜的抗拉强度增加了64.8%,断裂伸长率降低了14.7%,水蒸气透过系数显著降低。当MCC质量分数从0%增加到3%时,薄膜的氧气透过系数由2.145×10~(-16) cm~3·cm/(cm~2·s·Pa)降低到1.393×10~(-16) cm~3·cm/(cm~2·s·Pa),但当MCC质量分数为4%时,薄膜的氧气透过系数略有增加。MCC的加入使得薄膜的热稳定性提高,初始分解温度略有升高,当MCC质量分数为4%时,薄膜表面和横截断面局部区域可以观察到少量的大颗粒出现团聚现象。结论 MCC的加入提高了PVA薄膜的力学性能、疏水性、阻隔性、热稳定性,控制好其加入量可以有效改善PVA薄膜的性能。     

聚乙烯醇/玉米秸秆微晶纤维素复合膜的制备与性能

采用玉米秸秆微晶纤维素(CSCMC)作为增强剂,生物可降解材料聚乙烯醇(PVA)作为基体,制备了PVA/CSCMC复合膜材料,并对复合膜的结构、热稳定性能、力学性能进行了测试。结果表明,玉米秸秆微晶纤维素可增强复合膜材料的热稳定性能和力学性能。当CSCMC的质量分数为10%时增强效果最佳,与纯的PVA膜相比,复合膜的起始分解温度和最大重量损失率温度分别提高了19.25℃和17.17℃,拉伸强度提高了37.91%,断裂伸长率提高了58.93%。     

甘蔗渣微晶纤维素增强聚乙烯醇复合膜的性能研究

以甘蔗渣微晶纤维素(BCMC)作为增强材料,聚乙烯醇(PVA)作为基体,制备了BCMC/PVA复合膜材料,并对复合膜的结构、热稳定性能、力学性能进行了测试。结果表明,甘蔗渣微晶纤维素增强复合膜材料的热稳定性能和力学性能。当BCMC的质量分数为5%时增强效果最佳,与纯PVA膜相比,起始分解温度和最大重量损失率温度分别增加了11.71℃和36.86℃,拉伸强度提高了17.52%,断裂伸长率提高了29.58%。     

微晶纤维素/明胶对淀粉复合薄膜性能影响研究

探究微晶纤维素/明胶对淀粉复合膜热封、力学、热稳定性能等影响,以期提升淀粉基薄膜的综合性能。以不同比例微晶纤维素/明胶(1∶9,2∶8,3∶7)做增强相,溶液浇铸法制备多组分淀粉膜—微晶纤维素/明胶/淀粉膜(MCC/GL/ST)。通过扫描电镜(SEM)、差示量热扫描(DSC)、热重分析(TG)对薄膜进行表观形貌及热稳定性分析,采用热封仪、万能材料拉力机表征薄膜力学性能、热封性能。结果表明,与微晶纤维素/淀粉膜(MCC/ST)相比,微晶纤维素/明胶(2∶8)/淀粉膜(MCC/GL/ST-2)热封强度提高了352.9%,拉伸强度提高至9.12 MPa,红外光谱分析(FT-IR)表明MCC和GL之间存在氢键相互作用;薄膜阻隔性能随明胶添加量降低而提升,DSC及TG曲线表明MCC/GL/ST-2具有良好的热稳定性,可满足热封加工性的同时保证其性能稳定。     

纳米纤维素晶体增强补强聚乙烯醇薄膜性能研究现状

目的 综述近几年有关将纳米填料纳米纤维素晶体(CNC)作为增强补强剂,提高聚乙烯醇(PVA)薄膜的物理性能方面的研究,以期为PVA薄膜材料的进一步开发和应用提供参考。方法 通过对相关文献进行收集与整理,阐述PVA/CNC复合薄膜的应用现状,介绍CNC的形貌特性、化学改性及成膜方式对改善PVA/CNC薄膜物理性能的研究现状,综述CNC分散性、交联剂和成膜条件对提高PVA/CNC复合薄膜物理性能的影响。结论 通过增加CNC在PVA基体中的分散性,针对不同用途选择对应的成膜方式,这样可有效改善PVA薄膜的力学性能、阻隔性能和耐水性等,提高PVA薄膜的使用价值。     

聚乙烯醇/改性纳米纤维素晶体纳米复合薄膜的制备及性能

先用丁二酸酐对纳米纤维素晶体(NCC)进行表面羧基化改性,然后将改性NCC添加到聚乙烯醇(PVA)基体中制备PVA/改性NCC纳米复合薄膜,并进一步热处理制得交联PVA/改性NCC纳米复合薄膜。通过热重分析、差热分析、吸水实验和拉伸实验考察了改性NCC的添加量对薄膜性能的影响,以及加热交联对薄膜性能的影响。结果表明,与纯PVA薄膜相比,添加改性NCC后,薄膜的起始分解温度升高、结晶峰向高温方向移动,吸水率基本不变,力学性能对环境湿度敏感;热处理交联后,薄膜的起始分解温度继续升高、结晶峰也向高温方向移动,吸水率显著降低,力学性能不随环境湿度变化。     

APTES改性微晶纤维素对淀粉复合薄膜性能影响

目的 探究3-氨丙基三乙氧基硅烷（3-AminopropylTriethoxysilane,APTES）改性微晶纤维素（MicrocrystallineCellulose,MCC）对淀粉基复合薄膜的影响,以期改性得到的硅烷化微晶纤维素（Silanized Microcrystalline Cellulose, MMCC）能够提高淀粉基薄膜的性能。方法 在90℃下糊化淀粉后加入MCC或MMCC,以溶液浇铸法制备淀粉基复合薄膜,采用扫描电子显微镜（SEM）、热重分析（TGA）等测试手段对复合薄膜进行表观形貌和热性能分析,借助万能材料试验机、接触角测量仪等仪器对薄膜进行力学性能、耐水性能、吸湿性能等分析。结果 以APTES改性MCC后的MMCC(MCC与APTES质量比5∶1)掺入淀粉所制备的薄膜MMCC-2/ST,复合薄膜拉伸强度较原淀粉膜（Native Starch Film, ST）提高了230%,水接触角为106.4°,相较于原淀粉膜（Starch Film, ST）提高了60.8°。结论 通过实验表明,MMCC对淀粉基薄膜的力学性能、耐水性能等有较好提升,从而拓宽了淀粉基薄膜在包装...     

均匀设计法优化聚乙烯醇/甲基纤维素薄膜吸湿性的研究

为优化薄膜的制备工艺,采用均匀设计法,对聚乙烯醇(PVA)/甲基纤维素(MC)薄膜吸湿性进行了研究。试验以PVA/MC的体积比、甘油含量、pH、戊二醛浓度为考察因素,以吸湿率为考察指标,建立了4因素7水平均匀设计试验,应用SPSS软件对数据进行了多元一次回归分析。结果表明:影响薄膜吸湿性的因素主次顺序为戊二醛浓度甘油含量体积比pH;当PVA与MC体积比为2:1,甘油含量为0.11mL/(100mL),pH为3.06,交联剂浓度为2.26×10-4 mol/L时,制得的薄膜吸湿率为2.68,抗张强度为42.17MPa,伸长率为48.2%,性能较优。     

离子液体法微晶纤维素/聚乙烯醇共混膜的制备及性能

以离子液体为微晶纤维素(MCC)和聚乙烯醇(PVA)的共溶剂,采用液-固相转变法制备MCC/PVA共混膜。共混膜经红外光谱(FT-IR)、扫描电镜(SEM)、热重分析(TGA)、接触角测试和拉力试验等表征。FT-IR和SEM分析结果表明,两组分间有很好的相容性,用甲醇做沉淀剂可以制备出孔径均一的纳米共混膜。TGA和力学性能测试结果表明,共混膜具有良好的综合热稳定性、拉伸强度及尺寸稳定性。     

纳米纤维素晶体和柠檬酸改性聚乙烯醇薄膜的制备及性能

以球形纳米纤维素晶体(NCC)作增强相、柠檬酸作交联剂对聚乙烯醇(PVA)进行改性,制备了PVA/NCC纳米复合薄膜和柠檬酸交联PVA/NCC纳米复合薄膜。通过热重分析、差热分析、吸水实验和拉伸实验考察了NCC的添加和柠檬酸的交联对薄膜热性能、耐水性和力学性能的影响。结果表明,与纯PVA薄膜相比,改性PVA薄膜的起始分解温度升高、熔融/结晶峰向高温方向移动、吸水率降低;只用NCC或柠檬酸对PVA改性时,所得PVA/NCC纳米复合薄膜、柠檬酸交联PVA薄膜的力学性能均对环境湿度敏感;同时用NCC(m(NCC)/m(PVA)=6/100)和柠檬酸(m(柠檬酸)/m(PVA)=3/100或m(柠檬酸)/m(PVA)=4.5/100)对PVA改性时,所得柠檬酸交联PVA/NCC纳米复合薄膜的力学性能不随环境湿度变化。     

聚乙烯醇水凝胶与聚乙烯薄膜的表面粘接

用铬酸氧化方法处理聚乙烯(PE)薄膜,得到了表面刻蚀均匀的化学改性薄膜;利用XPS、IR表征了薄膜表面的化学变化,采用SEM、AFM、接触角表征了薄膜表面微观结构和物理性能。制备可化学交联及物理交联成水凝胶的聚乙烯醇(PVA)溶液,与表面刻蚀的PE薄膜复合,得到了PVA水凝胶与PE薄膜的表面复合材料。通过剥离强度测定、SEM观察,表明PVA水凝胶与PE薄膜很好地粘接在一起。     

Effects of Grinding with Microcrystalline Cellulose and Cyclodextrins on the Ketoprofen Physicochemical Properties

Ground mixtures of ketoprofen (KETO) with native crystalline β-cyclodextrin, amorphous statistically substituted methyl-β-cyclodextrin, and microcrystalline cellulose were investigated for both solid phase characterization (differential scanning calorimetry (DSC) powder X-ray diffractometry, and infrared (IR) spectrometry) and dissolution properties (dispersed amount and rotating disk methods) to evaluate the role of the carrier on the performance of the final product. The effects of different grinding conditions, partial sample dehydration, and 1 year storage at room temperature were also investigated. The results pointed out the importance of the carrier nature on the efficiency of the cogrinding process. Both cyclodextrins were much more effective than was microcrystalline cellulose, even though no true inclusion complex formation occurred by mechanochemical activation. The best results were obtained from ground mixtures with methyl-β-cyclodextrin, which showed the best amorphizing and solubilizing power toward the drug and permitted an increase of approximately 100 times its intrinsic dissolution rate constant, in comparison with the approximate 10 times increase obtained from ground mixtures with β-cyclodextrin.     

Compaction Properties of Microcrystalline Cellulose Using Tableting Indices

The compaction properties of microcrystalline cellulose (MCC) from 6 different sources were investigated and compared using tableting indices. The 50-μm and 100-μm grades were studied in order to determine lot-to-lot variability within a source, variability between sources, and the influence of storage conditions on the compaction properties of MCC. Two lots of each grade of MCC were obtained from each source and tested as received. It was found that the Avicel and Emcocel products demonstrated the most similarities based on tableting indices. Significant lot-to-lot differences in the tableting indices were observed for Fibrocel, Omnicel, and Spectrum MCC products. The brittle fracture index was low for all products tested and not significant. Storage of compacts at elevated humidity conditions prior to determining the tableting indices decreased the magnitude of the tensile strength, dynamic indentation hardness, and bonding index. Particle size analysis revealed differences between the labeled mean particle size and the experimentally determined value for some of the MCC grades and sources investigated. The percent weight gain of MCC powder at 18 hr was less than 0.6% at 30% relative humidity, and ranged from about 0.75% to 1.46% at 51% and 75% relative humidities. The x-ray diffraction patterns were similar for the MCC grades and sources investigated. MCC products from different sources are not directly substitutable based on the differences in physicomechanical properties observed for the tableting indices.     

The Improvement in Mechanical and Barrier Properties of Poly(Vinyl Alcohol)/Graphene Oxide Packaging Films

In this study, poly(vinyl alcohol) (PVA)‐graphite oxide and PVA‐graphene oxide (XGO) films were prepared by simple and environmentally friendly method. Fourier transform infrared spectroscopy, X‐ray diffraction and scanning electron microscope revealed the strong hydrogen‐bonding interactions between XGO and PVA matrix and the layered structure of tensile fracture surfaces of exfoliated PVA‐XGO films. These resulted in a remarkable improvement on mechanical and barrier properties of XGO/PVA nanocomposite films. The addition of 0.3 and 2.0 wt.% XGO showed an increase in tensile strength (49%) and failure stain (13–22%), in comparison with the neat PVA films. The dramatic improvement of 144% in elastic modulus was observed in PVA/2.0 wt.% XGO. Both O₂ and water vapour permeability coefficients of PVA film decreased by about 76% and 21% at an XGO loading of 2.0 wt.%, respectively. Preliminary test was performed to determine the use of nanocomposite films to extend the shelf life of bananas. It was found that bananas packaged in nanocomposite films were ripened slower than those unpackaged or packaged in PVA films. These results demonstrate that such films could dramatically promote the application of PVA‐based films in the packaging industry. Copyright © 2015 John Wiley & Sons, Ltd.     

聚乙烯醇/聚丙烯酸/羟基磷灰石复合高吸水性树脂的制备及溶胀行为

以聚乙烯醇(PVA)、部分中和的丙烯酸(AA)和羟基磷灰石(HA)为原料,过硫酸铵(APS)为引发剂,N,N′-亚甲基双丙烯酰胺(MBA)为交联剂,采用水溶液聚合法制备了聚乙烯醇/聚丙烯酸/羟基磷灰石(PVA/PAA/HA)复合高吸水树脂。考察了PVA用量对吸水性能的影响,研究了树脂在不同pH值溶液和不同阳离子盐溶液中的溶胀行为。结果表明,引入适量的PVA有利于树脂吸水性能的改善;树脂在pH=4～11较宽的范围内都能保持较高的吸水倍率,在CaCl2溶液中的溶胀动力学行为表现出明显的"过溶胀平衡现象"。     

Devazipide (MK-329) Adsorption on Microcrystalline Cellulose

Abstract

An in-depth evaluation of the adsorption of Devazipide onto microcrystalline cellulose, formulation and/or process optimization procedures to minimize this adsorption are reported. This adsorption was more evident in the 1 mg compared to the 10 mg strength tablet and could be completely eliminated if the microcrystalline cellulose was reduced to <10%. This adsorption followed the Langmuir Isotherm and was dependent on pH with insignificant amount of adsorption occurring at pH 2.0. At this particular pH, adsorbed drug is easily released.     

氧化微晶纤维素交联壳聚糖复合膜的制备及性能

目的 制备氧化微晶纤维素交联壳聚糖复合膜,并探索交联改性对壳聚糖复合薄膜性能的影响。方法 首先采用高碘酸钠氧化法对微晶纤维素进行氧化处理,制备氧化微晶纤维素,再通过溶液共混流延法制备不同质量分数(0%、1%、3%、5%、7%、9%)的氧化微晶纤维素交联壳聚糖复合薄膜。通过对复合薄膜组分、形貌、力学性能、光学性能、热稳定性及阻隔性能的表征,考察不同含量的氧化微晶纤维素对壳聚糖薄膜各性能的影响。结果 氧化微晶纤维素表面的醛基能与壳聚糖中的氨基发生交联反应,氧化微晶纤维素的加入可以改善壳聚糖薄膜的拉伸强度和断裂伸长率,复合薄膜的拉伸强度和断裂伸长率最大分别达到了43.07 MPa和19.42%;随着氧化微晶纤维素含量的增大,复合薄膜的紫外屏蔽性能增强,水蒸气透过系数增高,但热稳定性未见明显变化。结论 采用氧化微晶纤维素交联改性壳聚糖可以有效改善壳聚糖薄膜的力学性能和紫外屏蔽性能,有助于进一步扩大其包装应用范围。