Panaitescu Denis Mihaela, Vizireanu Sorin, Stoian Sergiu Alexandru, Nicolae Cristian-Andi, Gabor Augusta Raluca, Damian Celina Maria, Trusca Roxana, Carpen Lavinia Gabriela, Dinescu Gheorghe
Polymer Department, National Institute for Research and Development in Chemistry and Petrochemistry, 202 Spl. Independentei, 060021 Bucharest, Romania.
National Institute for Laser, Plasma and Radiation Physics, Atomistilor 409, Magurele-Bucharest, 077125 Ilfov, Romania.
Polymers (Basel). 2020 Jul 7;12(7):1510. doi: 10.3390/polym12071510.
Microcrystalline cellulose (MCC) was surface modified by two approaches, namely a plasma treatment in liquid using a Y-shaped tube for oxygen flow (MCC-P) and a TEMPO mediated oxidation (MCC-T). Both treatments led to the surface functionalization of cellulose as illustrated by FTIR and XPS results. However, TEMPO oxidation had a much stronger oxidizing effect, leading to a decrease of the thermal stability of MCC by 80 °C. Plasma and TEMPO modified celluloses were incorporated in a poly(3-hydroxybutyrate) (PHB) matrix and they influenced the morphology, thermal, and mechanical properties of the composites (PHB-MCC-P and PHB-MCC-T) differently. However, both treatments were efficient in improving the fiber-polymer interface and the mechanical properties, with an increase of the storage modulus of composites by 184% for PHB-MCC-P and 167% for PHB-MCC-T at room temperature. The highest increase of the mechanical properties was observed in the composite containing plasma modified cellulose although TEMPO oxidation induced a much stronger surface modification of cellulose. This was due to the adverse effect of more advanced degradation in this last case. The results showed that Y-shaped plasma jet oxidation of cellulose water suspensions is a simple and cheap treatment and a promising method of cellulose functionalization for PHB and other biopolymer reinforcements.
微晶纤维素（MCC）通过两种方法进行表面改性，即使用Y形管进行液体中的氧等离子体处理（MCC-P）和TEMPO介导的氧化（MCC-T）。FTIR和XPS结果表明，两种处理均导致纤维素的表面功能化。然而，TEMPO氧化具有更强的氧化作用，导致MCC的热稳定性降低80°C。将等离子体和TEMPO改性的纤维素掺入聚（3-羟基丁酸酯）（PHB）基体中，它们对复合材料（PHB-MCC-P和PHB-MCC-T）的形态、热性能和力学性能产生不同的影响。然而，两种处理在改善纤维-聚合物界面和力学性能方面均有效，在室温下，PHB-MCC-P复合材料的储能模量提高了184%，PHB-MCC-T复合材料的储能模量提高了167%。尽管TEMPO氧化对纤维素的表面改性更强，但在含有等离子体改性纤维素的复合材料中观察到力学性能的最高提高。这是由于后一种情况下更高级降解的不利影响。结果表明，纤维素水悬浮液的Y形等离子体射流氧化是一种简单、廉价的处理方法，是用于PHB和其他生物聚合物增强材料的纤维素功能化的一种有前景的方法。
