论文总字数：29592字

摘 要

炎热夏季强烈的太阳光照射会使建筑物和露天设备的外壁及内部温度升高、热量积聚，大大降低了人们的生活舒适度、增加了降温成本和能耗并且存在大量的安全隐患。聚氯乙烯(PVC)，作为一种通用塑料，其户外用品的使用量日益增加，因此对PVC进行降温功能改性研究势在必行。

由于无机有机复合材料能够很好地综合无机物和有机物的优异特性而展现出突出的物理化学特性，本实验拟使用金红石型二氧化钛(TiO₂)对PVC进行功能改性，使其具备较好的太阳光反射率而达到理想的降温效果。将PVC基材与TiO₂进行熔融共混，考察TiO₂含量对PVC/TiO₂共混体系耐候性、降温性能、太阳光反射率以及力学性能的影响。

本实验采用太阳光模拟器、自制降温效果测试装置、精密色差仪、紫外-可见-近红外分光光度计(UVPC)、冲击试验机以及电子万能试验机等对材料性能进行了表征分析。实验结果表明，PVC/TiO₂共混体系的太阳光反射性能和降温效果随着TiO₂添加量的增大而增强。当PVC/TiO₂共混体系中TiO₂达到10 phr，其共混材料在可见光区和近红外区的反射率以及总反射率分别为92.21 %、73.20 %和78.22 %。由于TiO₂是一种刚性无机粒子，添加到PVC基材后，共混材料的冲击韧性有所下降，但弯曲模量和断裂伸长率随着TiO₂添加量的增大而增大。TiO₂的加入对PVC/TiO₂共混体系的拉伸强度和弯曲强度的影响不大。同时发现TiO₂能极大地提高PVC的耐紫外光性能，对延长户外使用寿命有着积极意义。

关键词: 聚氯乙烯；金红石型二氧化钛；太阳光反射率；降温性能；紫外光老化

Study on the solar reflectance and application in cooling field of PVC/TiO₂ blends

Abstract

The strong solar irradiation in hot summer results in the accumulation of internal heat and rising of the external walls of the buildings and outdoor equipment, which greatly reduces the living comfort of people, as well as increases the cooling costs for cooling purpose and energy consumption. Besides, this also leads to massive potential safety hazard. Polyvinyl chloride (PVC), as a general-purpose plastic, the use of its outdoor products is becoming increasingly wider. Therefore, it is imperative to carry out the research on the cooling function of PVC.

Since inorganic-organic composites show outstanding physical and chemical properties due to the perfect combination of the excellent properties of both inorganic solid and organic polymer, in this study, rutile titanium dioxide (TiO₂) was used to functionally modify PVC, aiming to give the blends high solar reflectance and excellent cooling effect. The PVC matrix was mixed with TiO₂ via melt blending. The effects of TiO₂ content on the weather resistance, cooling performance, solar reflectance and mechanical properties of PVC/TiO₂ bends were investigated.

In this study, the properties of materials were characterized and analyzed by solar simulator, self-made device for temperature test, precision color difference meter, UV-Vis-NIR spectrophotometer (UVPC), Izod impact tester and universal testing machine. The experimental results showed that the solar reflectance and cooling effect of PVC/TiO₂ bends were enhanced with the increasing loading content of TiO₂. When the addition of TiO₂ was 10 phr, the reflectance in the visible and near infrared regions as well as total solar reflectance of the bends respectively were 92.21 %, 73.20 % and 78.22 %. Since the TiO₂ particles are rigid, after adding them to PVC matrix, the impact toughness of the composite material decreased, but its flexural modulus and elongation at break increased with the increasing loading content of TiO₂. In addition, the addition of TiO₂ had little effect on the tensile strength and flexural strength of PVC/TiO₂ blends. At the same time, it was found that TiO₂ can greatly improve the UV resistance of PVC, which had positive effect on the prolongation of the life of the material when used outdoors.

Keywords: polyvinyl chloride ; rutile titanium dioxide; solar reflectance; cooling property; ultraviolet aging

目 录

摘 要 I

Abstract II

第一章 前言 1

1.1 课题背景 1

1.2 PVC简介 2

1.3 TiO₂简介 2

1.4 国内外进展 3

1.5 本课题的工作内容 4

第二章 理论部分 5

2.1 TiO₂屏蔽紫外光抗老化机理 5

2.2 降温机理 5

2.3 Rayleigh光散射定律 6

第三章 实验部分 7

3.1 原料 7

3.2 实验仪器与设备 7

3.3 实验配方 7

3.4 PVC/TiO₂共混材料的制备 8

3.5 测试与表征 9

3.5.1 老化试验 9

3.5.2 色差分析 9

3.5.3 UVPC测试 9

3.5.4 降温性能测试 10

3.5.5 力学性能测试 12

第四章 结果与讨论 13

4.1 UVPC测试分析 13

4.1.1 未老化样品太阳光反射性能 13

4.1.2 200 h老化样品太阳光反射性能 14

4.1.3 400 h老化样品太阳光反射性能 15

4.1.4 600 h老化样品太阳光反射性能 16

4.2 太阳光反射降温性能测试 17

4.2.1 室外实际高温环境测试 17

4.2.2 太阳光模拟器测试 18

4.2.3 600 h老化样品太阳光模拟器测试 19

4.3 色差分析 20

4.1.1 共混物表面颜色变化数码照片 20

4.1.2 ΔE值变化曲线 20

4.1.3 Δa值变化曲线 22

4.1.4 Δb值变化曲线 23

4.1.5 ΔL值变化曲线 24

4.4 力学性能测试 25

4.4.1 冲击性能 25

4.4.2 拉伸性能 26

4.4.3 弯曲性能 27

第五章 结论 28

参考文献 29

致 谢 32

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