【作者】 赖学军；

【导师】 曾幸荣；

【作者基本信息】 华南理工大学 ， 材料学， 2012， 博士

【摘要】 聚丙烯（PP）作为五大通用塑料之一，广泛应用于汽车工业、房屋装饰、电子电气等领域。然而，PP遇火易燃烧，放热量大且伴随着大量的熔滴，严重限制了其应用范围。因此，对PP进行阻燃研究显得尤为重要。膨胀阻燃技术是近年发展最快的无卤阻燃技术之一，为制备高性能无卤阻燃PP提供了方法和思路。本论文主要针对现有膨胀型阻燃剂（IFR）阻燃效率偏低、耐水性能差和热稳定性不足的缺点，首先制备了焦磷酸三聚氰胺（MPP），并将其与季戊四醇（PER）复配组成IFR阻燃PP。在此基础上，研究了聚硼硅氧烷（pBSil）、芳基磷酸酯及其纳米复合物对PP/IFR的协同阻燃作用。研究了热塑性聚氨酯包覆IFR母料对PP的阻燃作用。此外，还合成了三嗪大分子成炭剂（TBM），将其与MPP复配阻燃PP，制备了具有优良阻燃性能、耐水性能和热稳定性能的阻燃PP材料，并深入探讨了其阻燃机理。主要研究内容和结果包括：第一，以三聚氰胺、焦磷酸钠等为原料，制备了MPP，并将其与PER复配阻燃PP。研究了MPP/PER对PP力学性能、阻燃性能及热稳定性能的影响，并借助热重分析（TGA）、傅立叶变换红外光谱（FT-IR）和热重-红外联用（TG-FTIR）等方法探讨了其阻燃机理。结果表明：MPP具有优良的热稳定性能和突出的耐水性能。MPP与PER复配对PP具有良好的阻燃抑烟作用。当MPP/PER的总用量为25wt%、质量比为3:1时，阻燃PP的极限氧指数（LOI）为29.0%，垂直燃烧级别达到UL-94V-1级；其热释放速率峰值（pHRR）、平均热释放速率（av-HRR）、总热释放（THR）、平均质量损失速率（av-MLR）和最大比消光面积（pSEA）较PP分别下降了67.7%、66.2%、26.6%、52.2%和63.6%。MPP/PER的可能阻燃机理为：受热燃烧时，MPP/PER先后经历了脱水酯化、交联成炭和发泡膨胀等一系列反应，形成具有隔热隔氧效果的多孔膨胀炭层，覆盖在PP基体上层，从而起到阻燃作用。第二，采用间苯二酚双（二苯基）磷酸酯（RDP）与IFR复配阻燃PP，研究了RDP对PP/IFR力学性能、流变性能、阻燃性能以及热稳定性能的影响。研究发现：RDP与IFR对PP表现出良好的协同阻燃作用；RDP改善了膨胀炭层的质量及其高温稳定性，形成了更为厚实、致密的炭层。同时，RDP的加入可以改善IFR与PP基体的相容性。动态热机械分析（DMA）结果表明，RDP对PP/IFR复合材料具有一定的增塑和增韧作用；随着RDP用量的增加，PP/IFR复合材料的储能模量（E′）和玻璃化转变温度（Tg）逐渐下降。动态流变分析结果表明，RDP的加入降低了PP/IFR复合材料的储能模量（G′）、损耗模量（G′′）、损耗因子（tanδ）和复数黏度（η*），改善了PP/IFR的加工性能。第三，分别以环糊精纳米海绵体（NS）和蒙脱土（MMT）为载体装载RDP，制备了含磷纳米海绵体（P-NS）和含磷蒙脱土（P-MMT），并研究了其对PP/IFR复合材料的协同阻燃作用。研究发现：P-NS、P-MMT与IFR均具有显著的协同阻燃作用，且大幅提高了PP/IFR的热稳定性能。X射线衍射分析（XRD）结果表明，RDP对MMT具有良好的插层改性作用。经RDP改性处理后，MMT的层间距从1.22nm增大到了2.15nm。此外，与以OTAC改性的有机蒙脱土（O-MMT）相比，P-MMT具有更高的热稳定性，并对PP/IFR具有更好的协同阻燃效果。第四，以八甲基环四硅氧烷、正硅酸乙酯和硼酸等为原料制备了pBSil，并研究其与IFR对PP的协同阻燃作用。结果表明：pBSil的加入改善了IFR与PP的相容性。与硼酸锌、4A分子筛和纳米二氧化硅相比，pBSil对PP/IFR表现出更为优异的阻燃抑烟作用。当pBSil的用量为3.0wt%时，材料的LOI从29.0%提高到35.0%，垂直燃烧级别从UL-94V-1级提高到UL-94V-0级。TGA、TG-FTIR和FT-IR等分析结果表明，pBSil的加入改善了IFR的热稳定性能，促进了IFR的成炭，并改善了膨胀炭层的致密度和热稳定性，从而提高了材料的阻燃性能。第五，采用热塑性聚氨酯（TPU）为载体树脂，通过熔融包覆，制备了TPU包覆膨胀阻燃母料（TPU-e-IFR），研究了TPU-e-IFR对PP力学性能、阻燃性能、热稳定性能及耐水性能的影响。结果表明：TPU改善了IFR与PP基体的相容性，提高了阻燃PP的力学性能。差示扫描量热（DSC）结果表明，由于TPU的阻隔作用，IFR的初始酯化温度从198oC提高到了213oC。与IFR相比，TPU-e-IFR具有更为优良的热稳定性能、成炭性能、耐水性能和阻燃效率。第六，以三聚氯氰、乙醇胺和二乙烯三胺等为原料，通过亲核取代反应合成了TBM，并将其与MPP复配阻燃PP。通过FT-IR、元素分析、固体13C-NMR等对TBM的化学结构进行了表征。TGA结果显示，TBM的初始热失重温度为298°C，700°C时的残炭率高达38.7wt%。TBM还具有优良的耐水性能，相同温度下，其在水中的溶解度仅为PER的1/20~1/10。MPP与TBM对PP具有良好的协同阻燃作用。当MPP和TBM的用量分别为16.7wt%和8.3wt%时，PP/MPP/TBM的LOI为31.0%，达到UL-94V-0级；材料的pHRR、THR和av-MLR较PP分别下降了77.1%、31.4%和58.1%。同时，阻燃PP还具有优异的耐水性能，经70oC的热水中浸泡168h后，仍能通过UL-94V-0测试。更多还原

【Abstract】 Polypropylene (PP) as one of the five major common plastics has been widely used inmany fields, such as automobiles, housing decorations, electronic and electrical appliances,etc. However, its inherent flammability and burning with dripping have severely restricted itsfurther application. Therefore, it is very important to improve the flame retardancy of PP. Inrecent years, intumescent flame-retardant technique is one of the fastest growingflame-retardant technologies, which provides methods and ideas to prepare high performancehalogen-free flame retardant PP. In this dissertation, lots of research work has been carried outto overcome the deficiencies of the existing intumescent flame retardants (IFR), such as lowefficiency, poor water resistance, thermal instability, and so on. Firstly, melaminepyrophosphate (MPP) was prepared, and used together with pentaerythritol (PER) to form anovel IFR system to flame retard PP. Then, the synergistic effects of polyborosiloxane (pBSil),aryl phosphate and its nanocomposites on PP/IFR composite were studied. Moreover, theeffect of flame retardant masterbatch using thermoplastic polyurethane (TPU) as carrier resinto encapsulate IFR on flame retardant PP was also investigated. Furthermore, a novel charringagent triazine-based macromolecule (TBM) was synthesized, and combined with MPP toflame retard PP. Accordingly, flame retardant PP with highly efficient flame retardancy,outstanding water resistance and good thermostability were prepared, and theirflame-retardant mechanism was intensively studied. The main research contents and resultsare listed as following:First, MPP was synthesized by using melamine and sodium pyrophosphate, and was usedtogether with PER to flame retard PP. The effects of MPP/PER on the mechanical properties,flame retardancy and thermostability of PP were investigated. And the flame-retardantmechanism of MPP/PER was explored by thermogravimetric analysis (TGA), Fouriertransform infrared (FT-IR) and TG-FTIR, etc. The results showed that MPP possessed goodthermostability and outstanding water resistance. PP/MPP/PER composite had good flameretardancy and low smoke release. When the total content of MPP/PER was25wt%, and themass ratio of MPP to PER was3:1, the limiting oxygen index (LOI) value of flame retardantPP was29.0%, and the vertical burning test achieved a UL-94V-1rating. Meanwhile,compared with PP, the peak heat release rate (pHRR), average heat release rate (av-HRR),total heat release (THR), average mass loss rate (av-MLR) and peak specific extinction area(pSEA) of PP/MPP/PER were reduced by67.7%,66.2%,26.6%,52.2%and63.6%,respectively. Furthermore, the possible flame-retardant mechanism of MPP/PER was revealed.When being heated and burned, the IFR generates a swollen multicellular char after undergoing esterification, crosslinking and foaming reaction between MPP and PER, acting asa physical barrier, which slows down heat and mass transfer between gas and condensedphases, thus protecting the underlying material from burning.Second, resorcinol bis(diphenyl) phosphate (RDP) was used together with IFR to flameretard PP, and the effects of RDP on the mechanical properties, rheological properties, flameretardancy and thermostability of PP/IFR composite were studied. It was found that there wasa good synergistic effect between RDP and IFR on flame retardant PP. The addition of RDPimproved the quality and thermostability of the swollen char, forming a more compact anddense char layer. Moreover, RDP could improve the compatibility between IFR and PPsubstrate, thus improving the mechanical properties of the composite. The dynamicmechanical thermal analysis (DMA) result showed that RDP had plasticization andtoughening effects on the PP/IFR composite. With the RDP content increasing, the storagemodulus (E’) and glass transition temperature (Tg) gradually decreased. Meanwhile, thedynamic rheological analysis results showed that, the storage modulus (G′), loss modulus(G′′), loss factor (tanδ) and complex viscosity （η*） of the PP/IFR composite were decreasedwith the addition of RDP, indicating that the processability of the composite was improved.Third, phosphorus-containing nanosponge (P-NS) and phosphorus-containingmontmorillonite (P-MMT) were prepared by loading RDP onto cyclodextrin nanosponge (NS)and montmorillonite (MMT), respectively. And they were utilized as synergistic agents toimprove the flame retardancy of the PP/IFR composite. It was found that both P-NS andP-MMT had significant synergistic effects with IFR on flame retardant PP, and thethermostability of PP/IFR composite was significantly improved. The X-ray diffraction (XRD)results showed that, after modified by RDP, the interlayer spacing of MMT was increasedfrom1.22nm to2.15nm, indicating that RDP was a good organophilic-modification agent tofunctionalize MMT. In addition, compared with the O-MM modified by octadecyl trimethylammonium chloride (OTAC), P-MMT showed higher thermostability and better synergisticeffect with IFR on flame retardant PP.Fourth, a novel synergistic agent containing boron and silicon, namely polyborosiloxane(pBSil) was prepared via the condensation reaction of boric acid, tetraethoxysilane andoctamethyl cyclotetrasiloxane. The obtained pBSil was then combined with IFR to flameretard PP, and the effects of pBSil on the mechanical properties, flame retardancy andthermostability of the PP/IFR composite were investigated. It was found that pBSil couldimprove the compatibility between IFR and the PP matrix, thereby improving the mechanicalproperties of the composite. Compared with zinc borate, zeolite and nano-silica, pBSilshowed much better flame retardancy and smoke suppression on the PP/IFR composite. When the content of pBSil was3.0wt%, the LOI value of flame retardant PP was increased from29.0%to35.0%, and the UL-94rating was improved from V-1to V-0rating. The TGA, FT-IRand TG-FTIR results showed that, pBSil could enhance the thermostability of IFR, andpromote the char formation. Moreover, the compactness and thermostability of theintumescent char were significantly improved, thus resulting in the improvement of the flameretardancy of the composite.Fifth, a novel flame-retardant masterbatch, namely TPU-e-IFR, using thermoplasticpolyurethane (TPU) as carrier resin to encapsulate IFR, was adopted to flame retard PP. Theeffects of TPU on the mechanical properties, flame retardancy, thermostability andwater-resistance of the flame retardant PP were investigated. The results showed that thedispersion of the IFR and the compatibility between the IFR and PP matrix were improved byTPU, which was responsible for the enhancement of mechanical properties and flameretardancy of the PP/IFR composite. The differential scanning calorimetry (DSC) resultshowed that the initial esterification temperature of IFR was increased from198oC to213oCby incorporation of TPU, thus effectively preventing the esterification reaction between MPPand PER during the processing of the composite. In comparison with IFR, TPU-e-IFR hadbetter thermostability, charring performance, water resistance and flame retardancy.Finally, a novel charring agent triazine-based macromolecule (TBM) was synthesized byusing cyanuric chloride, ethanolamine and diethylenetriamine via nucleophilic reaction, andwas combined with MPP to flame retard PP. The chemical structure of TBM wascharacterized by FT-IR, elementary analysis, and solid-state13C-NMR. And the TGA resultshowed that the initial decomposition temperatures of TBM was298°C, and the residue charof TBM at700°C was as high as38.7wt%. Additionally, TBM exhibited much lower watersolubility than PER. The solubility of TBM was only1/20~1/10of PER at the sametemperature. Moreover, TBM showed an obviously synergistic effect with MPP in flameretardant PP. When the content of MPP was16.7wt%and TBM was8.3wt%, the LOI valueof the PP/MPP/TBM composite was31.0%, and the vertical burning test reached a UL-94V-0rating. Meanwhile, the pHRR, THR and av-MLR of the composite were77.1%,31.4%and58.1%lower than those of the PP matrix, respectively. Furthermore, the composite exhibitedan outstanding water resistance and could still obtain a UL-94V-0rating after being soaked in70oC water for168h.更多还原