Preparation and properties of paraffin solid-solid phase change materials

doi:10.16085/j.issn.1000-6613.2022-0670

Abstract

Abstract:

Paraffin (PA) phase change materials are difficult to emulsify and disperse, and ion crosslinking is used to finalize the design. Based on the hydrophilic and easy ionizing properties of polyacrylic acid (PAA) carboxyl group, the grafted paraffin of low polymerization degree polyacrylic acid (PAA) was designed. The paraffin emulsion was prepared by self-emulsification method. Paraffin solid-solid phase change materials (PA SS-PCMs) were prepared in water medium in a short period. The morphology of PA emulsion and PA SS-PCMS were characterized and analyzed by scanning electron microscope. The molecular structure, crystallization performance and thermal stability of paraffin graft products and PA SS-PCMS were tested and analyzed by infrared spectrometer, X-ray diffractometer, polarizing microscope, differential scanning calorimeter and thermogravimetric analyzer. The results showed that the setting method was universal to different kinds of paraffins, and paraffin solid-solid phase change materials with high energy storage efficiency could be obtained by grafting modification and ion crosslinking. The results indicated that adding 55^# paraffin (PA1) twice, reducing the proportion of PA1 input in the early stage and adding PA1 without participating in the reaction in the later stage, could effectively improve the self-emulsification capacity and phase change energy storage capacity of the graft products. On this basis, PA1 SSt-PCMs with AA∶PA1∶BPO mass ratio of 1.8∶15(10+5)∶0.05 were prepared with a crystallization temperature of 45.52℃ and an enthalpy of crystallization of -182.28J/g. The enthalpy of crystallization loss was 3.05% after 100 cycles with high energy storage density and good thermal storage stability.

Key words: paraffin, graft modification, self-emulsification, solid-solid phase change material, ion crosslinking

摘要：

针对石蜡（PA）相变材料难以乳化分散、离子交联定型的问题，利用聚丙烯酸（PAA）羧基的亲水性，易离子化特性，设计了低聚合度PAA接枝石蜡，以自乳化方法制备石蜡乳液，通过常温离子交联，在水介质中、短周期内制备了石蜡固-固相变材料（PA SS-PCMs）。利用扫描电子显微镜对PA乳液及PA SS-PCMs的形貌进行了表征、分析，利用红外光谱仪、X射线衍射仪、偏光显微镜、差示扫描量热仪、热重分析仪对石蜡接枝产物及PA SS-PCMs的分子结构、结晶性能、热稳定性进行了测试和分析。结果表明：该定型方法对不同种类石蜡具有普适性，通过接枝改性、离子交联能得到较高储能效率的石蜡固-固相变材料。研究发现：分两次添加55^#石蜡（PA1），前期减少PA1的投入占比，后期添加不参与反应的PA1，能有效提高接枝产物的自乳化能力及相变储能能力。在此基础上，制备了AA∶PA1∶BPO质量比为1.8∶15(10+5)∶0.05的PA1 SSt-PCMs，其结晶温度为45.52℃，结晶焓为-182.28J/g，循环100次后结晶焓损失3.05%，具有较高的储能密度和良好的储热稳定性。

关键词: 石蜡, 接枝改性, 自乳化, 固-固相变材料, 离子交联

CLC Number:

TK02

ZHAO Xipo, BIAN Wuxun, RAN Baoqing, LIU Jinchao, YIN Shaoding, SUN Yiming. Preparation and properties of paraffin solid-solid phase change materials[J]. Chemical Industry and Engineering Progress, 2023, 42(2): 897-906.

赵西坡, 卞武勋, 冉宝清, 刘进超, 尹少鼎, 孙义明. 石蜡固-固相变材料的制备及性能[J]. 化工进展, 2023, 42(2): 897-906.

Figures/Tables 16

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原料	规格	生产商
丙烯酸（AA）	AR	国药集团化学试剂有限公司
过氧化苯甲酰（BPO）	AR	阿拉丁（上海）有限公司
氢氧化钠	AR	国药集团化学试剂有限公司
氯化锌	AR	麦克林化学试剂有限公司
二甲苯	AR	国药集团化学试剂有限公司
去离子水	—	实验室自制

原料	规格	生产商
丙烯酸（AA）	AR	国药集团化学试剂有限公司
过氧化苯甲酰（BPO）	AR	阿拉丁（上海）有限公司
氢氧化钠	AR	国药集团化学试剂有限公司
氯化锌	AR	麦克林化学试剂有限公司
二甲苯	AR	国药集团化学试剂有限公司
去离子水	—	实验室自制

原料	缩写	规格	生产商
石蜡1	PA1	55^#，工业纯	中佳新材料科技有限公司
石蜡2	PA2	47^#，工业纯	中佳新材料科技有限公司
纯石蜡	PA3	42^#，工业纯	中佳新材料科技有限公司
切片石蜡	PA4	58^#，试剂纯	国药集团化学试剂有限公司
微晶蜡	PA5	60^#，工业纯	东光县金涛蜡制品厂

原料	缩写	规格	生产商
石蜡1	PA1	55^#，工业纯	中佳新材料科技有限公司
石蜡2	PA2	47^#，工业纯	中佳新材料科技有限公司
纯石蜡	PA3	42^#，工业纯	中佳新材料科技有限公司
切片石蜡	PA4	58^#，试剂纯	国药集团化学试剂有限公司
微晶蜡	PA5	60^#，工业纯	东光县金涛蜡制品厂

样品	AA/g	PA/g	自乳化
PA1-SSf	1.8	15（PA1）	失败
PA1-SSt	1.8	10+5（PA1）	成功
PA1-SSa	2.7	10（PA1）	成功
PA1-SSb	3.6	10+5（PA1）	成功
PA2-SS	2.7	10（PA2）	成功
PA3-SS	2.7	10（PA3）	成功
PA4-SS	2.7	10（PA4）	成功
PA5-SS	2.7	10（PA5）	成功