【作者】 刘微；

【导师】 张胜；

【作者基本信息】 北京化工大学 ， 材料科学与工程， 2010， 博士

【摘要】 尼龙66(PA66)织物近年来被广泛应用于民用、军用服装以及家装等方面。PA66纤维作为世界上最早实现工业化的合成纤维,具有较好的力学性能以及尺寸稳定性,但由于具有织物比表面面积大的特点,PA66织物容易燃烧,其燃烧时的熔融滴落容易造成火势蔓延,融滴物也易于灼伤皮肤,造成人员伤亡,因此对PA66织物进行阻燃整理是十分有必要的。目前市面上常用的PA66后整理阻燃剂主要是通过高温半软化面料从而使阻燃剂渗入织物内部的方法达到阻燃目的的,但是此法的阻燃耐久性不佳,且对织物的其它物理性能损失较大,而国内外针对PA66织物的阻燃后整理的研究较少,迄今为止还未有开发出一种环保、高效、经济的PA66织物后整理阻燃体系。本论文首次将表面紫外光接枝技术引入织物的阻燃后整理中。较其他接枝改性方法而言,光接枝技术条件温和,在引发表面接枝反应的同时并不会对基材本身性能造成影响,通过此法改性的织物可与阻燃剂以共价键形式连接,提高了阻燃的耐久性,同时此项技术具有工艺简单,易于操作,污染低等优点。光接枝技术多用于改善织物、纤维的染色性能,亲水性能以及生物相容性等,迄今尚未见有将光接枝技术应用于织物阻燃后整理研究的报道。为了提高PA66织物的阻燃性能,研究中分别采用了一步光接枝改性法以及两步表面改性法对织物进行阻燃改性,一步法是在织物表面直接光接枝引入阻燃单体从而改善织物阻燃性能的方法,分别选取了光敏性单体丙烯酰胺(AM)及2-羟基乙基甲基丙烯酸酯磷酸酯(HEMAP)作为阻燃单体改善PA66织物的阻燃性能,两步法则是先通过光接枝聚合在织物表面引入活性基团,之后活性基团再与阻燃单体反应,进而达到耐久阻燃目的的方法,本研究中此法是以马来酸酐作为光接枝接枝单体,将马来酸酐接枝链引入织物表面,再将三乙醇胺与接枝链上的酸酐活性基团反应。研究中首次将丙烯酰胺(AM)以及2-羟基乙基甲基丙烯酸酯磷酸酯(HEMAP)用于织物阻燃,2-羟基乙基甲基丙烯酸酯磷酸酯更是首次用于材料阻燃,因此研究中试图对其阻燃机理进行深入探讨,为将来选择合适的PA66光接枝后整理阻燃剂提高了实验依据。本文采用以丙酮为溶剂,二苯甲酮为光引发剂,将丙烯酰胺光接枝于PA66织物表面,探索了单体、引发剂浓度,辐照时间以及整理工艺对光接枝率的影响,用ATR-FTIR、XRD、织物表面SEM照片、氧指数测试、垂直燃烧测试、热性能分析(TG、DTG)和锥形量热对改性织物结构和阻燃性能进行表征及评估。将阻燃测试结果与残余物剖面的SEM照片与气相TG-FTIR综合分析,对AM-g-PA66的阻燃机理进行了初步探讨。实验表明,当接枝率达到32.5%时,LOI值可达到26.2,垂直燃烧时无余燃和阴燃,无融滴,炭长6.8cm。洗涤10次后,仍可保持原LOI值的91.6%,洗涤50次后,阻燃性能降低较多,通过机理分析初步推测丙烯酰胺对PA66织物主要是以气相阻燃机理为主,通过聚丙烯酰胺接枝链提前分解释放出难燃气体NH3稀释可燃气体浓度,阻止火焰蔓延,从而达到改善阻燃性能的目的,研究中为了进一步提高阻燃耐久性,将光交联剂N,N’-亚甲基双丙烯酰胺(MBAAm)引入改性体系,实验表明,当MBAAm用量为0.05%,AM用量为20%,引发剂为2.0%时,可同时兼顾织物的的阻燃性及耐久性。研究中的第二个体系是以丙酮为溶剂,二苯甲酮为光引发剂,将2-羟基乙基甲基丙烯酸酯磷酸酯(HEMAP)光接枝于PA66织物表面,通过对单体、引发剂浓度,辐照时间,整理工艺等条件的探索得到光接枝的最佳工艺。采用ATR-FTIR,织物表面SEM照片、氧指数测试、垂直燃烧测试、热性能分析(TG, DTG)、锥形量热对改性织物结构和阻燃性能进行表征及评估。实验表明,当表面含磷量达到11%时,织物的LOI值可达到31.2,垂直燃烧时,离火自熄,无融滴,炭长5.2cm,洗涤50后,LOI值为26.2。结合残炭表面SEM照片、气相TG-FTIR分析和残炭红外及XPS分析,初步推断HEMAP对织物主要以凝聚相阻燃机理为主,通过PHEMAP接枝链在高温下热降解生成焦磷酸,多聚磷酸等促进成碳的化合物,提高残炭量,从而达到阻燃目的。同时还通过Flynn-Wall-Ozawa, Kissinger方法对两种改性的织物进行热氧化降解动力研究,通过对其反应活化能的计算和分析,推断出不同的阻燃机理可以导致活化能变化趋势的差别,但两者的活化能都较未改性前明显提高。两步法是以马来酸酐作为光接枝接枝单体,将马来酸酐接枝链引入织物表面,再将三乙醇胺与接枝链上的酸酐活性基团反应。通过对辐照时间、单体浓度、接枝反应时间以及接枝温度等条件的探索,得到了最佳光接枝及化学接枝工艺。用ATR-FTIR, XRD,织物表面SEM照片,氧指数测试,垂直燃烧测试,热性能分析(TG, DTG),锥形量热对改性织物结构和阻燃性能进行表征及评估。结果表明,当织物增重为6.6%时,LOI值为29.1,水洗10次后,LOI值为25.7,洗涤剂洗涤10次后,LOI值下降明显。更多还原

【Abstract】 PA66 fiber as the world’s first synthetic industrialized fiber has been widely used in military and civilian clothing, furnishings, upholstered furniture due to its excellent properties including good mechanical properties, low cost, resistance to shrinkage and pleasant aesthetics and so forth. However, PA66 fabric is easy to burn because of its higher specific surface area. And the melting drip during the burning might cause another fire and harm people’s life. Therefore, there is an urgent need to improve the flame retardancy of PA66 fabric. At present, most flame retardant finishing used for PA66 fabric involves to the semi-softening of the substrate, which cause the infiltration of flame retardant into the fabric and the treated fabric has the low durability and the bad mechanical properties. Meanwhile, study on the flame retardant finishing of PA66 fabric is rarely. Until now, none of those technologies has achieved any substantial commercial success. In this study, surface photografting technology has been used in the flame retardant finishing of PA66 fabric. Photografting is often used in fabric surface modification to improve the wettability, biocompatibility and dyeability since it is an economical, environmentally sustainable and effective method for surface modification of materials without altering bulk properties. However, its application in flame retardant finishing of the fabric has been rarely reported. It is suggested that this could be the first time to use photografting technology to enhance the flame retardancy of fabric.The one-step modificaiton and the two-step photografting modification have been used to improve the flame retardancy of PA66 fabric. In the one-step approach, acrylamide (AM) and 2-hydroxyethyl methacrylate phosphate (HEMAP) have been used as the monomers. Maleic anhydride (MAn) and triethanolamine system has been used in the two-step approach. And the flame retardant mechanism has been investigated in this study in order to guide the future research.Acrylamide has used as a grafting monomer with benzophenone (BP) as photoinitiator to modify the sample surface in order to improve flame retardancy of the PA66 fabric. The effects of monomer concentration, photoinitiator concentration, irradiation time and finishing process on photografting have been investigated in this study. Flame retardancy and the chemical structure of the PA66 fabric have been studied by ATR-FTIR, XRD, SEM photo, LOI testing, the vertical burning testing, thermal analysis and cone calorimetry. The results show that untreated PA66 fabric sample has a LOI value of 19.9 while AM-g-PA66 fabric sample with DP of 32.5% has a LOI value of 26.2, which is 32% higher than that of the untreated sample and the sample has the shorter after-flame time, the shorter char length and no melt dripping in the vertical burning test. AM-g-PA66 could keep 91.6% of the original LOI after 10 cycles of washings with 0.5% commercial grade detergent solution. Combined to TG-FTIR and SEM photo of the residue, it is proposed that the improved flame retardancy of AM-g-PA66 fabric may be due to the earlier thermal degradation of fabric which can cause a rapider shrinkage and an earlier decompositon of amide groups from the grafting chains to release NH3 which can prevent fire from spreading.2-hydroxyethyl methacrylate phosphate (HEMAP) as a grafting monomer and benzophenone (BP) as the photoinitiator has been used in the second system. The effects of monomer concentration, photoinitiator concentration, irradiation time and finishing process on photografting have been investigated. Flame retardancy and the chemical structure of the PA66 fabric have been studied by ATR-FTIR, LOI testing, the vertical burning testing, thermal analysis and cone calorimetry. The results show that P-g-PA66 fabric sample with P of 11% has a LOI value of 31.2 and has no melt dripping, no after-flame time, the shorter char length in the vertical burning test and the grafted sample could keep the LOI value of 26.1 after 50 cycles of washings with 0.5% commercial grade detergent solution. Combined to TG-FTIR, FTIR, XPS analysis and SEM photo of the residue, it is suggested that the improved flame retardancy of P-g-PA66 fabric may be due to the formation of phosphoric and polyphosphoric acids during the thernal oxidative degradation of the grafting chains, which as the dehydration agents drives the the formation of the heat resistant carbonaceous char by carbonisation. According to Kissinger and Flynn-Wall-Ozawa method, the activation energies have been calculated, indicating that the difference in the change of the activation energy could be attributed to the different flame retardant mechanism. However, compared to the ungrafted PA66 fabric, both AM-g-PA66 fabric and P-g-PA66 fabric have the higher activation energies.In the two step approach, surface photografting modification with maleic anhydride (MAn) under UV irradiation in association with a post reaction with triethanolamine has been used to improve the flame retardancy of polyamide66 (PA66) fabric. The effects of irradiation time and monomer concentration on the fabric surface grafting were investigated. Flame retardancy and thermal decomposition behaviour of the samples have been characterized by limiting oxygen index test (LOI), thermal analysis, cone calorimetry and it shows that flame retardancy of the treated PA66 fabric samples has been significantly improved. The chemical structures of the treated samples’surface were characterized by attenuated total reflection infrared spectroscopy (ATR-FTIR). The results show that MAn-g-PA fabric sample reacted with triethanolamine has the LOI value of 29.1 and the sample’s LOI value of about 25.7 is still retained after 10 cycles of water rinsing. However, MAn-g-PA fabric sample reacted with triethanolamine loses its flame retardancy after 10 cycles of washings with 0.5% commercial grade detergent solution. It is suggested the grafted chain is easy to degrade in the commercial grade detergent solution because of the alkaline condition.更多还原