Effect of Simulated Weathering on Physicochemical Properties and Inherent Biodegradation of PLA/PHA Nonwoven Mulches
Effect of Simulated Weathering on Physicochemical Properties and Inherent Biodegradation of PLA/PHA Nonwoven Mulches
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DOI：
10.1007/s10924-014-0697-0
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发表时间：
2014-12-01
影响因子：
5.3
通讯作者：
Narayan, Ramani
中科院分区：
文献类型：
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作者：
Hablot, Elodie;Dharmalingam, Sathiskumar;Narayan, Ramani
研究了模拟气候对四种完全生物基和潜在生物降解农业覆盖物的物理化学性质和生物降解性的影响，这些覆盖物由平均直径为7-16 μ m的随机取向纤维组成。使用纺粘加工由聚乳酸（PLA）制备两种覆盖物，一种为天然白色，另一种为黑色（分别为SB-W和SB-B），两种通过熔喷加工由100%PLA和PLA与聚羟基链烷酸酯的75/25 w/w共混物[PHA;聚（3-羟基丁酸酯-共-4-羟基丁酸酯）;分别为MB-PLA和MB-PLA+PHA]制备。SB-W和SB-B的拉伸强度高于MB-PLA和MB-PLA+PHA（分别为56.2N、37.1N、8.96N和3.90N）。模拟风化对SB的物理化学性质产生了微小的变化，但增强了固有的生物降解性，在90天内产生68- 72%的矿化。模拟风化极大地影响了MB覆盖物的物理化学性质，特别是MB-PLA+PHA，其在21天的风化循环期间经历了95%的拉伸强度损失、32%的重均分子量降低（从95.4至70.5kDa）和微纤维断裂。风化加速了两种MB覆盖物的生物降解，生物降解的时间过程和最终生物降解程度（90天内91- 93%）几乎与纤维素阳性对照的值相匹配。傅立叶变换红外光谱表明SB和MB覆盖物进行水解和光降解断链（诺里什II型反应）。SB非织造布可能被证明是有用的生物基和可堆肥材料，用于多季覆盖和其他长期农业应用，如多年生作物系统中的行覆盖。MB非织造布可能更适合于更传统的农业覆盖应用。
The effect of simulated weathering on the physicochemical properties and biodegradability of four fully biobased and potentially biodegradable agricultural mulches prepared nonwoven textile technology, consisting of randomly oriented fibers of average diameter 7-16 mu m, has been investigated. Two mulches were prepared from polylactic acid (PLA) using spunbond processing, one naturally white and the other black (SB-W and SB-B, respectively), and two via meltblown processing, from 100 % PLA and a 75/25 w/w blend of PLA and polyhydroxyalkanoate [PHA; poly (3-hydroxybutyrate-co-4-hydroxybutyrate); MB-PLA and MB-PLA+PHA, respectively]. SB-W and SB-B possessed higher tensile strength than MB-PLA and MB-PLA+PHA (56.2N, 37.1N, 8.96N, and 3.90N, respectively). Simulated weathering introduced minor changes in physicochemical properties of SBs, but enhanced inherent biodegradability, yielding 68-72 % mineralization in 90 days. Simulated weathering greatly affected the physicochemical properties of the MB mulches, particularly MB-PLA+PHA, which underwent a 95 % loss of tensile strength, 32 % decrease of weight-averaged molecular weight (from 95.4 to 70.5 kDa), and breakage of microfibers, during a 21 days weatherometry cycle. Weathering accelerated the biodegradation of both MB mulches, with the time course of biodegradation and final extent of biodegradation (91-93 % in 90 days) nearly matching the value obtained for the cellulosic positive control. Fourier transform infrared spectroscopy suggested the SB and MB mulches underwent hydrolysis and photodegradative chain scission (Norrish Type II reaction). SB nonwovens may prove useful as biobased and compostable materials for multi-season mulching, and other long-term agricultural applications, such as for row covers in perennial cropping systems. MB nonwovens may be better suited for more traditional agricultural mulch applications.