New Approach to Shape Memory Polymer Composite Production Using Alkaline Lignin-Reinforced Epoxy-Based Shape Memory...

Area of Science:

• Materials Science
• Polymer Science
• Biocomposites

Background:

• Shape memory polymers (SMPs) are of great interest, with ongoing research into multifunctional composites.
• Fossil-based resources for SMP composites raise environmental concerns, driving interest in renewable, biobased alternatives.
• Alkaline lignin, a natural polymer, is explored as a sustainable reinforcement for SMPs.

Purpose of the Study:

• To develop alkaline lignin-reinforced shape memory polymer composites (SMPCs).
• To investigate the thermo-mechanical, morphological, and shape memory properties of these novel SMPCs.
• To evaluate the effect of varying alkaline lignin content on SMPC performance.

Main Methods:

• Differential scanning calorimetry (DSC) to analyze thermal transitions (Tg).
• Dynamic mechanical analysis (DMA) to assess storage modulus and mechanical damping.
• Three-point bending tests to determine flexural modulus.
• Scanning electron microscopy (SEM) for morphological analysis.

Main Results:

• Alkaline lignin addition at 1% and 3% increased the glass transition temperature (Tg), while 5% decreased it.
• Storage modulus and bending modulus increased with higher alkaline lignin content, peaking at 5%.
• SEM revealed a rougher morphology at 1-3% lignin, transitioning to a smoother, plasticized surface at 5% lignin.

Conclusions:

• Alkaline lignin effectively reinforces SMPs, enhancing mechanical properties such as storage and flexural modulus.
• The optimal alkaline lignin content for improved mechanical performance and a smoother surface morphology is 5%.
• Increased lignin content improves polymer-alkaline lignin interaction, leading to a harder composite structure.