Metal hydroxides （MAH） consisting of magnesium hydroxide and aluminum hydroxide with a mass ratio of 1：2 were surface-modified by y-diethoxyphosphorous ester propyldiethoxymethylsilane, boric acid and diphenylsilan...Metal hydroxides （MAH） consisting of magnesium hydroxide and aluminum hydroxide with a mass ratio of 1：2 were surface-modified by y-diethoxyphosphorous ester propyldiethoxymethylsilane, boric acid and diphenylsilanediol in xylene under dibutyl tin dilaurate catalyst at 140 ℃. Phosphorus, silicon and boron elements covalently bonded to metal hydroxide particles were detected by X-ray photoelectron spectroscopy. The degradation behavior of the surface-modified MAH was characterized by thermogravimetric analysis. The results show that linear low density polyethylene （LLDPE） composite, filled with 50% （mass fraction） of MAH modified by 5.0% （mass fraction） of modifiers, passes the V-0 rating of UL-94 test and shows the limited oxygen index of 34%, and its heat release rate and average effective heat combustion in a cone calorimeter measurement decrease obviously; The mechanical properties of MAH can be improved by surface-modification. The uniform dispersion of particles and strong interfacial bonding between particles and matrix are obtained.展开更多
近年来,农田微塑料污染严重,对土壤健康及农作物安全产生了极大风险。为探究微塑料对土植系统的影响程度,采用水稻栽培试验,设置不同质量分数(0、0.5%、1.5%)和不同粒径(150、500μm)的低密度聚乙烯微塑料(Low density polyethylene,LD...近年来,农田微塑料污染严重,对土壤健康及农作物安全产生了极大风险。为探究微塑料对土植系统的影响程度,采用水稻栽培试验,设置不同质量分数(0、0.5%、1.5%)和不同粒径(150、500μm)的低密度聚乙烯微塑料(Low density polyethylene,LDPE)处理,探究LDPE对土壤养分含量、水稻生长和生理特性的胁迫情况。结果表明:微塑料增加水稻生长前中期(返青期、分蘖期和拔节期)表层(0~10 cm)和中层(10~20 cm)土壤总有机碳(TOC)含量6.06%~43.24%,降低后期(抽穗期和黄熟期)TOC含量6.10%~20.53%,深层土壤(20~30 cm)变化趋势与之相反,同时,可显著降低不同土层土壤全氮(TN)含量5.23%~53.73%和全磷(TP)含量2.01%~24.66%。微塑料促进水稻前期株高3.42%~18.32%,抑制中后期水稻株高1.90%~13.96%,减少水稻产量7.80%~24.83%。微塑料显著降低水稻净光合速率(Pn)6.36%~40.46%、气孔导度(Gs)3.40%~67.36%和胞间CO_(2)浓度(Ci)3.66%~21.86%,并显著增加蒸腾速率(Tr)10.79%~82.37%和饱和水汽压差(VPD)14.16%~109.60%,叶片蒸腾速率受到叶片VPD和Gs的协同影响,Gs减少使得水蒸汽难以从叶肉细胞扩散到气孔表面,而VPD增加极大地迫使水蒸汽从叶片表面扩散到周围环境,VPD的促进效果远大于Gs的抑制效果,最终出现Gs与Tr趋势相反的情况。此外,微塑料降低叶绿素a含量0.27%~3.48%,叶绿素b含量0.36%~3.92%,总叶绿素含量0.59%~3.47%。研究结果可为微塑料对土壤健康及水稻生长胁迫效应提供数据支撑和科学依据。展开更多
基金Project(20574020) supported by the National Natural Science Foundation of ChinaProject(20061001) supported by the Opening Project of the Key Laboratory of Polymer Processing Engineering, Ministry of Education, ChinaProject (20060106-2) supported by Guangdong Key Projects
文摘Metal hydroxides （MAH） consisting of magnesium hydroxide and aluminum hydroxide with a mass ratio of 1：2 were surface-modified by y-diethoxyphosphorous ester propyldiethoxymethylsilane, boric acid and diphenylsilanediol in xylene under dibutyl tin dilaurate catalyst at 140 ℃. Phosphorus, silicon and boron elements covalently bonded to metal hydroxide particles were detected by X-ray photoelectron spectroscopy. The degradation behavior of the surface-modified MAH was characterized by thermogravimetric analysis. The results show that linear low density polyethylene （LLDPE） composite, filled with 50% （mass fraction） of MAH modified by 5.0% （mass fraction） of modifiers, passes the V-0 rating of UL-94 test and shows the limited oxygen index of 34%, and its heat release rate and average effective heat combustion in a cone calorimeter measurement decrease obviously; The mechanical properties of MAH can be improved by surface-modification. The uniform dispersion of particles and strong interfacial bonding between particles and matrix are obtained.
