【作者】 张宇；

【导师】 任亮；

【作者基本信息】 长春工业大学 ， 高分子化学与物理， 2020， 硕士

【摘要】 聚乳酸(PLA)是一种环保无毒可生物降解且具有优异加工性的高分子材料,被称为最有前景的“绿色塑料”,在我国被大量使用,但是没改性的PLA属于易燃塑料,严重地限制了PLA在某些领域的广泛使用,因此研究环保型阻燃剂对可再生资源PLA进行阻燃改性就显得尤为重要。本文通过溶液聚合方法合成三种带有磷氮基团的环保型阻燃剂,采用元素分析、傅里叶红外光谱分析及热失重测试对三种磷氮阻燃剂进行表征。将三种磷氮阻燃剂分别应用到PLA树脂中,用垂直燃烧和极限氧指数对制备的三种复合材料进行阻燃性能分析,同时用冲击和拉伸测试对复合材料进行力学性能分析,最后对复合材料进行热失重分析及扫描电镜分析以研究三种阻燃剂的阻燃机理。主要研究工作及结论如下:1.将苯基磷酰二氯加入香兰素中进行溶液反应,然后加入缚酸剂,再加入对苯二胺进行聚合反应并对其产物进行了表征。通过傅里叶红外光谱和元素分析测试,表明成功地合成磷氮阻燃剂PPV。阻燃性能测试结果表明,PPV的加入使PLA复合材料有良好的阻燃效果。当体系中加入15%的PPV时,氧指数测试中LOI值为28.2相对于纯PLA增加了33.6%,垂直燃烧级别达到了UL-94 V-0级。同时,复合材料力学性能略有下降,影响较小。TG表明,复合材料有良好的热稳定性,700°C时的残炭量为10.4%,当体系中加入20%的PPV时,残炭量为12.3%,扫描电子显微镜(SEM)观察到规整、紧密的炭层,进一步证实复合材料具有良好的阻燃性。2.采用溶液聚合技术,分别将对苯二甲醛、间苯二甲胺和间苯二甲醛、对苯二胺加入到聚合体系中,然后引入DOPO进行聚合反应,合成目标产物磷氮阻燃剂PPD和PVD,并对两种阻燃剂进行了表征。通过傅里叶红外光谱分析证实合成了阻燃剂PPD和PVD。元素分析表明了产物PPD和PVD纯度较高。通过差示扫描量热仪(DSC)发现这两种阻燃剂与PLA有很好的相容性。磷氮阻燃剂PPD和PVD对PLA树脂起到了良好的阻燃效果,当添加量为15%时,PLA复合材料达到UL-94 V-0级,极限氧指数LOI值分别增加了34.1%和36.5%。复合材料在达到700°C时的残炭量分别为2.6%和11.2%。通过扫描电子显微镜(SEM)观察到炭渣表面致密,这种致密的结构很好地阻止了热量传递,保护PLA基体内部,起到了很好的阻燃效果,这与TG、DSC测试结果相一致。更多还原

【Abstract】 Polylactic acid(PLA)is an environmentally friendly,non-toxic and biodegradable polymer material with excellent processability.It is called the most promising “green plastic”,which is widely used in China.However,the unmodified PLA belongs to flammable plastics,which limits the wide use in some fields seriously.Therefore,it is particularly important to study environmentally friendly flame retardant modification of renewable resource PLA.In this study,three kinds of environmentally friendly flame retardants with phosphorus and nitrogen groups were synthesized by solution polymerization.The three kinds of phosphorus-nitrogen flame retardants were characterized by elemental analysis,Fourier transform infrared spectrum(FTIR)and Thermo gravimetric analysis(TGA).Then the three phosphorus-nitrogen flame retardants were applied to the PLA resin to analyze the flame retardancy of three prepared composites by vertical burning and Limiting oxygen index(LOI).At the same time,the mechanical properties of the composites were analyzed by impact and tensile tests.Finally,Thermo gravimetric analysis(TGA)and Scanning Electron Microscope(SEM)analysis were carried out to study the flame retardancy mechanism of the three flame retardants.The main research work and conclusions are as follows:1.First phenyl dichloro sphosphineoxid was added to vanillin for solution reaction.Next add the deacid reagent.Then add p-phenylenediamine for polymerization and characterized the synthesis.By Fourier transform infrared spectrum(FTIR)and elemental analysis test,it indicated that phosphorus-nitrogen flame retardant PPV was successfully synthesized.The test results of flame retardancy showed that the addition of PPV made PLA composites have good flame retardancy effect.When 15% flame retardant PPV was added to the system,limiting oxygen index(LOI)test showed that the LOI was 28.2,which was 33.6% higher than pure PLA.And the vertical burning could reach UL-94V-0 rating.Meanwhile,the mechanical properties of the composites decreased slightly but made a small influence.Thermo gravimetric analysis(TGA)showed that the composite had good thermal stability,and the amount of residual carbon at 700℃ was 10.4%.When 20% flame retardant PPV was added,the amount of carbon residue was 12.3%.A regular,compact carbon layer was observed by Scanning Electron Microscope(SEM),further confirming the good flame retardancy of the composites.2.The solution polymerization technology was used to add p-Phthaldialdehyde,m-Xylylenediamine and m-Phthaldialdehyde,p-Xylylenediamine into the polymerization system,and then the DOPO was introduced to carry out the polymerization reaction.The target product phosphorus-nitrogen flame retardants PPD and PVD were synthesized and the two flame retardants were characterized.The synthesis of flame retardants PPD and PVD were confirmed by Fourier transform infrared spectrum(FTIR).Elemental analysis showed high purity of the product PPD and PVD.The two flame retardants were found to have good compatibility with PLA by differential scanning calorimeter(DSC).The phosphorus-nitrogen flame retardant PPD and PVD showed good flame retardant effect on PLA resin.When the addition amount was 15%,the two PLA composites reached the UL-94V-0 rating,the Limiting oxygen index(LOI)increased to 34.1% and 36.5%,respectively.Carbon residues of the two composites at 700℃ were 2.6% and 11.2%,respectively.Scanning Electron Microscopy(SEM)observed that the surface of carbon residue was compact and this compact structure well prevented heat transfer,protected the interior of PLA matrix and played a good flame retardant effect,which is consistent with TG and DSC test results.更多还原