Hard Segment Engineering in Thermoplastic Polyurethane Directs Interfacial Microphase Separation for Moisture...

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Conventional desiccants in sachets pose space and safety issues for packaging.
• Incorporating desiccants into polymer matrices is challenging due to poor filler dispersion and discontinuous transport pathways.

Purpose of the Study:

• To design and investigate a multiphase composite for enhanced moisture adsorption.
• To understand how thermoplastic polyurethane (TPU) hard segment (HS) ratio influences composite microstructure and performance.

Main Methods:

• Fabrication of a polypropylene/polyethylene glycol/thermoplastic polyurethane/molecular sieve (PP/PEG/TPU/MS) composite with varying TPU HS ratios.
• Microstructural analysis using Fourier transform infrared spectroscopy (FTIR).
• Moisture absorption kinetics and capacity testing, including Fickian diffusion modeling.

Main Results:

• A TPU HS ratio of 42% yielded a continuous interpenetrating hydrophilic network with optimal mesopore size and low density.
• Strong hydrogen-bonding interactions at 42% HS promoted uniform molecular sieve dispersion and interfacial adhesion.
• The PP/42-TPU/PEG/MS composite demonstrated the highest equilibrium moisture capacity and fastest adsorption kinetics.

Conclusions:

• Controlling the TPU HS ratio is critical for developing high-performance moisture-adsorbing polymer composites.
• The developed composite offers effective protection for humidity-sensitive products, outperforming conventional methods.
• Moisture transport is governed by diffusion, influenced by a plasticization effect at higher relative humidity.