I wonder the tendency of coefficient of thermal expansion (CTE) of polymer which has different chain structure. In my opinion, CTE will be higher when the polymer materials has high interaction between the polymer chain. But, some reference said it's not true. So, I want to receive some opinion by many researchers.
Dear Park Jun Woo, chain flexibility with multitude of possible conformation changes is the essential factors dominating linear CTE. Expansion happen once the barrier of intermolecular cohesive energy is bypassed, which is necessary for segmental chain motions, this is the reflected by the value of Tg. All factors working against chain flexibility will such as rigid segments, bulky side groups will work against the ease of thermal expansion, and will shift the temperatures to higher input. Other secondary factors such as heating rate and polymer composite and additives have their additional effects. My Regards
Polymers with high chain packing and small free volume typically exhibit a lower coefficient of thermal expansion (CTE). This is because:
Therefore, a polymer with high chain packing and small free volume generally has a lower CTE because both factors contribute to reducing the polymer's ability to expand when heated.
The general trend is that polymers with rigid, densely packed chains and low free volume tend to have lower coefficients of thermal expansion compared to polymers with more flexible, loosely packed chains. The rigidity and packing efficiency of the polymer backbone are key structural parameters controlling CTE.
Yes, if a polymer has high chain packing and small free volume, it generally has a low coefficient of thermal expansion (CTE). This is because the tightly packed polymer chains have less ability to expand when heated, leading to a low CTE.
The coefficient of thermal expansion (CTE) in polymers is influenced by chain flexibility, interchain interactions, topological arrangement, and mechanical interlocks. Flexible polymers typically exhibit higher CTE due to increased thermal fluctuations. High crosslinking density can reduce CTE in the rubbery state but increase it in the glassy state. Ordered structures can lead to anisotropic thermal expansion, while mechanical interlocks in composites may restrict chain movement and affect CTE. The relationship between chain structure and CTE is complex and depends on various factors.