Thermal stability of cellulose nanomaterials and their composites with polyvinyl alcohol (PVA)
Thermal stability of cellulose nanomaterials and their composites with polyvinyl alcohol (PVA)
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DOI：
10.1007/s10973-016-5791-1
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发表时间：
2016-12-01
影响因子：
4.4
通讯作者：
Gardner, Douglas J.
中科院分区：
文献类型：
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作者：
Rowe, Allison A.;Tajvidi, Mehdi;Gardner, Douglas J.
本研究探讨了由聚乙烯醇（PVA）与可生物降解的填料增强的复合材料的热稳定性：纤维素纳米晶体（CNC）或纤维素纳米纤丝（CNF）。PVA与CNC和PVA与CNF的组合在2、4、6和8重量%纤维素下经历几种不同的热重分析（TG）加热程序-恒定加热速率、等温和具有动态加热速率的高分辨率。干燥后，还在TG中测试起始材料（PVA粒料、PVA膜、11.8%固体的水性CNC和3%固体的水性CNF）。对主要热解阶段降解开始时和最大降解时的温度进行了量化。使用Flynn-Wall-Ozawa（FWO）方法计算动力学参数（活化能，指前因子）。与纯PVA相比，PVA基质中的CNC或CNF掺入在降解开始时或在热解的主要阶段的最大降解时没有显著地改变温度。然而，纳米纤维素的加入降低了最大降解速率，在更高的填料含量下降低更大。在主要降解峰之后，大部分复合材料的原始质量保持完整。将CNF掺入PVA复合材料中产生的膜的活化能高于纯PVA膜的活化能。
This study investigates the thermal stability of composites composed of polyvinyl alcohol (PVA) reinforced with biodegradable fillers: cellulose nanocrystals (CNC) or cellulose nanofibrils (CNF). Combinations of PVA with CNC and PVA with CNF at 2, 4, 6, and 8 % cellulose by weight underwent several different thermogravimetric analysis (TG) heating programs-constant heating rate, isothermal, and high resolution with a dynamic heating rate. The starting materials (PVA pellets, PVA film, aqueous CNC at 11.8 % solids, and aqueous CNF at 3 % solids) were also tested in the TG after drying. Temperatures at the onset of degradation and at maximum degradation for the principal pyrolysis stage were quantified. Kinetic parameters (activation energy, pre-exponential factor) were calculated using the Flynn-Wall-Ozawa (FWO) method. CNC or CNF incorporation in the PVA matrix did not markedly shift temperatures at the onset of degradation or at maximum degradation for the major stage of pyrolysis, compared to neat PVA. However, the inclusion of nanocellulose lowered the maximum rate of degradation, with larger reductions at higher filler contents. A larger portion of the composites' original mass remained intact following the major degradation peak. Incorporation of CNF in composites with PVA produced films with activation energies higher than the activation energy of neat PVA film.