尿素基改性LG对PP阻燃和抗氧化性能的影响

The Effect of Urea-based Modified LG on the Flame-retardant and Anti-oxidation Properties of PP

以尿素、棉秆木质素(LG)和甲醛为原料,通过曼尼希反应制备出尿素基改性棉秆木质素(UM-LG),然后将UM-LG和聚丙烯(PP)以一定比例复合,再复配一定比例的聚磷酸铵(APP)来研究对PP阻燃和抗氧化性能的影响。当棉杆木质素添加量为15份、APP添加量10份时氧化诱导时间(OIT)从3.61 min增加到了6.12 min,增加了69.5%;与纯PP的试样相比,微量混合流变实验1 min时扭矩增加了107.4%,说明UM-LG增强了PP的抗氧化性能;极限氧指数从17.8%增加到28.7%,SEM图中可以发现UM-LG和APP的添加使得PP在燃烧过程中形成了炭层,进一步说明了UM-LG增强了PP的阻燃性能,力学性能测试表明,随着UM-LG和APP的添加,PP的力学性能受到一定程度的影响。

Using urea,cotton stalk lignin(LG)and formaldehyde as raw materials,urea-based modified cotton stalk lignin(UM-LG)was prepared through Mannich reaction,and then UM-LG and polypropylene(PP)were mixed in a certain proportion,a certain proportion of ammonium polyphosphate(APP)was added to study the effect on the flame retardant and anti-oxidation properties of PP.When the cotton stalk lignin is added to 15 parts and the APP is added to 10 parts,the oxidation induction time(OIT)increases from 3.61 to 6.12 min.The increase rate is 69.5%.Comparing with the pure PP sample,the torque increases rate 107.4%in the micro-mixing rheological experiment for one minute,indicating that UM-LG enhances the oxidation resistance of PP.The limiting oxygen index increases from 17.8%to 28.7%and the increase rate is 57.9%.It can be found in the scanning electron microscope(SEM)that the addition of UM-LG and APP makes PP form a carbon layer during the combustion process,which further shows that UM-LG enhances the resistance of PP.Combustion performance and mechanical performance tests show that with the addition of UM-LG and APP,the mechanical properties of PP are affected to a certain extent.