纤维素-木质素辐射接枝共聚机理研究及其在全秸秆降解材料上的应用

With the increased environment pollution, more and more attentions have been paid utilization of biomass. The straw, as large output and short growth cycle has become truly inexhaustible and renewable resources. In this project, applicant presents to fabricate straw degradable materials to resolve the problems of waste plastic pollution and straw burning produced air pollution. At first, we separated rice straw into three main components, celluloses, lignins and hemicelluloses. After that, celluloses, lignins and hemicelluloses were purified with recyclable mixed organic solvents. Then, the poly (cellulose-co-lignin) was fabricated by irradiated copolymerization using cellulose as crosslinker, and lignin as functional monomer. Be exposed under 60Co γ irradiation, the cellulose’s hydrogen bonds breaks down, generates active free radicals, and copolymerizes with the lignins. Subsequently, hemicelluloses were introduced as plastination materials for plastifing poly (cellulose-co-lignin). After the treatment, the plasticity increased and the hydroxyl groups decreased. This change may good to fabricate straw particles. At last, the straw particles were fabricated using extrusion granulating machine. And the straw degradable potting containers were fabricated using injection molding machine. Among these steps, the most important step is celluloses copolymerized with lignins. Through copolymerized with lignins, cellulose’s hydrogen bonds decreased, plasticity increased and hydrophobicity increased. At the same time, the speed of degradability was controlled by the degree of copolymerization. This work can reduce “white pollution” and decrease the amount of straw burning. It has great scientific and social significance.

针对国内严峻的环境污染问题（塑料的“白色污染”和秸秆焚烧造成的空气污染），结合秸秆高效利用研究中存在的资源浪费问题，申请人提出了全秸秆农用设施材料的实验设想。首先，以秸秆为主体材料，提取纤维素、木质素和半纤维素；根据纤维素和木质素的结构特点，利用60Co-γ-射线的高能量破坏纤维素的氢键，再接枝木质素，得到接枝率可控的共聚物Poly(纤维素-co-木质素)；随后，利用半纤维素增塑Poly(纤维素-co-木质素)，得到塑性秸秆粉料；在造粒机、注塑机上制备全秸秆降解粒子和育苗钵。其中，纤维素辐照接枝木质素是本项目的研究重点：1、接枝木质素，有效减少了纤维素分子内氢键，增加了共聚物的塑性；2、接枝木质素，有效降低了纤维素的亲水性，通过调节接枝率达到控制降解速率的目的。该项目的展开能够实现全秸秆降解粒子的制备与应用，减少农田“白色污染”，降低年均秸秆燃烧量，具有及其重要的科学意义和社会价值。

本课题严格的按照项目计划和合同开展实验，如期完成了全部研究内容。.为了缓解日益严重的“白色污染”，项目开展了两种秸秆基降解育苗钵的研究。poly(纤维素-co-木质素)育苗钵：利用60Co γ射线的高能量辐照处理水稻秸秆，成功分离木质素、半纤维素和纤维素；60Co γ射线辐照接枝纤维素和木质素，得到共聚物poly(纤维素-co-木质素)；热压成型法制备poly(纤维素-co-木质素)育苗钵；钵内草莓育苗-机械连钵移栽-降解评估实验表明，育苗期育苗钵破碎率<5%，机械移栽后育苗钵3个月内全部碎裂，不影响作物根系生长，促早挂果5-7天。胶粘型育苗钵：纤维素为主体材料，两端含双键的交联剂为功能材料，制备功能型纤维素基溶胶；秸秆屑为主体材料，功能型溶胶为胶黏剂，制备胶粘型育苗钵；钵内南瓜育苗-机械连钵移栽-降解评估实验表明，育苗期育苗钵破碎率<8%，机械移栽后育苗钵3个月内全部碎裂，不影响作物根系生长，促早挂果5-7天。.通过项目的展开，我们成功研制了两种秸秆基全降解育苗钵，实现了生物质资源的大循环（农业废弃物—育苗钵—田间降解），为减少农业“白色污染”提供了新思路。