【作者】 赵伟；

【导师】 吕荣文；

【作者基本信息】 大连理工大学 ， 精细化工， 2009， 硕士

【摘要】 本文以菊粉、环氧氯丙烷和碳链长度十二、十四、十六和十八的烷基二甲基叔胺为原料,通过两种实验方法合成了取代度为0.46、0.6、0.8、1.01和1.33的十二烷基菊粉季铵盐阳离子表面活性剂和取代度约为0.8的十四、十六、十八烷基的菊粉季铵盐。用凯式定氮法确定了所合成的菊粉季铵盐阳离子表面活性剂的取代度。用红外光谱对十二烷基菊粉季铵盐的结构进行了表征,并研究了不同取代度十二烷基菊粉季铵盐的表面活性、泡沫性能、胶束热力学性质、增溶性能、复配性能、吸湿保湿性能以及对黄瓜的保鲜作用。以菊粉、环氧氯丙烷和烷基二甲基叔胺为原料制备不同取代度的菊粉季铵盐表面活性剂。分别考察了原料配比、碱的质量、碱化时间、反应温度和反应时间对取代度的影响。当采用合成方法Ⅱ时,对于十二烷基菊粉季铵盐,在n（菊粉）:n（环氧氯丙烷）:n（叔胺）=1:3:3时,碱的质量是0.3 g时,碱化时间为40 min,反应温度为70℃,反应时间为8 h时,取代度最高,达到1.44。表面张力和临界胶束浓度的测定结果表明,该类物质具有良好的表面活性。其中,十二烷基菊粉季铵盐的表面张力最低可以降到31.48 mN/m,临界胶束浓度为2.29E-4mol/L。热力学性质研究表明在标准状态下菊粉季铵盐的的胶束化过程可以自发进行,在298 K-313 K温度区间内形成胶束的过程为一吸热过程。各体系的-T△S_m⁰的绝对值均明显大于相应的△H_m⁰,自由能降低的贡献来自于熵,胶束形成过程是一个熵驱动过程。研究了菊粉季铵盐与十二烷基硫酸钠（SDS）复配体系的表面化学性质,计算了二者在混合胶束和表面吸附层中的协同作用参数。结果表明,复配体系的表面化学性能明显优于单一体系,在混合胶束和表面吸附层中都表现出强烈的协同效应。当n（菊粉季铵盐）:n（SDS）=8:2时,菊粉季铵盐复配体系的表面张力最低,由单一菊粉季铵盐体系的31.48 mN/m变为25.60 mN/m,此时,cmc最低,由单一菊粉季铵盐体系2.29E-4 mol/L的变为0.46×10^-4 mol/L。研究了菊粉季铵盐的泡沫性能和乳化性能。当DS=0.8时,表面活性剂溶液的初始泡沫体积为78 mL,5 min泡沫体积为76 mL,稳定系数为0.97。取代度为0.8的菊粉季铵盐对液体石蜡的乳化时间为187 min。对菊粉季铵盐的吸湿保湿性能及保鲜性能进行考察。对于取代度（DS）为0.8的产品,当RH=81%时,48 h吸湿率达到27.5%,在RH=43%时的48 h保湿率达到75.7%。菊粉季铵盐涂膜在黄瓜表面可以减缓水份的蒸发,减缓叶绿素和维生素C含量的降低,有一定的保鲜效果。取代度为0.8的菊粉季铵盐涂膜处理2 d以后的黄瓜维生素含量为0.193mg/g,叶绿素含量为0.326 mg/g;而未经涂膜处理的黄瓜维生素含量为0.145 mg/g,叶绿素含量为0.231 mg/g。更多还原

【Abstract】 A series of inulin quaternary ammonium salt were synthesized from inulin, epichlorohydrin and N,N-dimethyldodecylamine（N,N-dimethyltetradecylamine,N,N-dimethylhexadecylamine, N,N-dimethyloctadecylamine） via two methods.Meanwhile,the structure of the products was characterized by IR analysis and the degree of substitution（DS） of the products was analyzed by full-automatic azotometer.Then,the general physical-chemical properties,such as surface activity,foam and emulsifying ability,mixing ability and solubility were studied.Finally,the moisture absorption and retention properties and the preservation effect for cucumber were investigated.Aiming to get higher degree of substitution（DS） of the product,several experimental conditions were optimized,including raw material composition,amount of base,the duration time in base,reaction temperature and reaction time.The optimized conditions are as follows: the ratio of n（inulin）:n（epichlorohydrin）:n（N,N-dimethyldodecylamine） is 1:3:3,the amount of base is 0.3 g,the duration time in base is 40 min,reaction temperature is 70℃,and reaction time is 7 hours,DS achieves 1.44 when it reaches the optimized condition.The surface tension and cmc value of dodecyl inulin quaternary ammonium salt were 31.48 mN/m and 2.29E-4 mol/L respectively,which meant that this kind of surfactant had good surface activity.At the same time,the micelle thermodynamic parameters revealed that the micellization process was spontaneous,and gained heat in the temperature range of 298K and 313K.The absolute value of -T△S_m⁰ was larger than that of△H_m⁰,indicating the contribution of entropy to free energy.The surface properties calculation of the mixture of inulin quaternary ammonium salt and sodium dodecyl sulphate（SDS） showed that there was strong synergic effect in the mixture.The surface chemical performance of the mixture was significantly better than that of the monosurfactant system.The surface tension and cmc of the mixture is 25.60 mN/m and 0.46×10^-4 mol·L^-1 respectively when the ratio of n（inulin quaternary ammonium salt）:n（SDS） is 8:2.The foaming ability and emulsifying ability of inulin quaternary ammonium salt were also studied.The initial foam volume of inulin quaternary ammonium salt（DS=0.8） is 78 mL while the final foam volume is 76 mL with the stability coefficient is 0.97,meanwhile,the emulsifying time is 187 min for paraffin liduid.Finaly,the moisture absorption,moisture retention properties and the preservation effect for cucumber of the inulin quaternary ammonium salt were investigated.The moisture absorption ratio of inulin quaternary ammonium salt（DS=0.8） is 27.5%after 48 h when the relative humidity（RH） is 81%,and the moisture retention ratio could reach 75.7%after 48 h when RH is 4.3%.The preservation effect for cucumber coated with inulin quaternary ammonium salt can slow the loss of total chlorophyll and vitamin C during storage.The content of vitamin C and chlorophyll of the cucumber coated with inulin quaternary ammonium salt（DS=0.8） is 0.193 mg/g and 0.326 mg/g after two days while the content of vitamin C and chlorophyll is 0.145 mg/g and 0.231 mg/g respectively when the cucumber without coating.更多还原