聚乙烯醇——碱木质素发泡材料的制备与性能

为改善发泡材料存在的力学性能较差、成本高的现状,同时增加碱木质素的利用率,制备高性能的发泡材料,以聚乙烯醇(PVA)和碱木质素为原料,甲醛为交联剂,采用无机发泡原理,制备了聚乙烯醇--碱木质素发泡材料(PLFM),并测定其相关性能。结果表明:相对于PVA用量,碱木质素质量分数为33%、甲醛4/5(mL/g)、硫酸6/5(mL/g),固化温度为120℃时制备的发泡材料拉伸强度最大为25.91MPa,比纯聚乙烯醇泡沫材料的4.32MPa有了显著提升。不同聚合度PVA制备发泡材料:PVA0588聚合度较低,无法形成泡体;PVA1788-PLFM和PVA2488-PLFM相比,PVA2488-PLFM具有更好的拉伸强度,而且表观密度及吸水倍率更小。FTIR显示碱木质素与PVA均发生交联,大多发生在苯环5位上,与PVA2488交联效果好。SEM显示PVA2488-PLFM具有更好的孔隙结构。热分析中,DSC显示PVA1788-PLFM中有填充剂存在的木质素,PVA2488-PLFM中没有,表明PVA2488-PLFM的生物相容性好;TG和DTG显示,PVA2488-PLFM热失重最剧烈时温度为379℃,高于PVA1788-PLFM的360℃,但800℃时失重率为95.94%高于PVA1788-PLFM的80.13%,说明PVA2488-PLFM耐热性好,且易热降解。综上,PVA2488-PLFM的性能更佳。 

Preparation and properties of polyvinyl alcohol-alkali lignin foam material ( PLFM)

In order to improve the current situation of foam material with poor mechanical properties and high cost, increase the utilization of alkali lignin, and prepare foam materials with high performance, we prepared polyvinyl alcohol/alkali lignin foam material ( PLFM) based on inorganic foaming principles, with polyvinyl alcohol ( PVA) and alkali lignin as raw material and formaldehyde as crosslinking agent, and then measured its relevant performance. The results showed: relative to the amount of PVA, when the mass fraction of alkali lignin was 33%, formaldehyde at 4/5(ml/g), sulfuric acid at 6/5 (ml/g), and solidification temperature was 120℃, the maximum tensile strength of the prepared foam material is 25.91 MPa, which is remarkably improved compared to the 4.32 MPa of pure polyvinyl alcohol foam material. Comparing the foam materials prepared with different polymerization degrees of PVA: foam material with PVA0588l is unable to form foam due to lower polymerization degree. Compared with PVA1788-PLFM, the tensile strength of PVA2488-PLFM is better, and the apparent density and water absorbency ratio is smaller. FTIR showed that alkali lignin cross-linked with PVA, mostly in the 5thposition of the phenyl ring,and crosslinking effect with PVA2488 is better. SEM showed that PVA2488-PLFM has better pore structure. Regarding thermal performance, DSC showed that lignin as filler exists in PVA1788-PLFM, but not in PVA2488-PLFM, indicating that PVA2488-PLFM possesses better biocompatibility. TG and DTG showed that, the temperature while most intensive thermal weight loss of PVA2488-PLFM happened is 379 ℃,which is higher than that (360 ℃) for PVA1788-PLFM,however weight loss ratio is lower. At the same time, the weight loss ratio of 95.94% is also higher than that (80.13%) of PVA1788-PLFM,indicating that PVA2488-PLFM has good heat resistance, and conducive to thermal degradation. To sum up, PVA2488-PLFM has better performance.