Influence of Rheological and Morphological Characteristics of Polyhydroxybutyrate on Its Meltblown Process Behavior

Area of Science:

• Polymer Science
• Materials Science
• Biotechnology

Background:

• Polyhydroxybutyrate (PHB) is a biodegradable polymer with potential applications.
• Processing pure PHB presents challenges including degradation, slow crystallization, and poor stretchability.
• Limitations hinder PHB's use in thermoplastic processes for fiber formation.

Purpose of the Study:

• To screen commercial PHBs for properties relevant to meltblown processing.
• To identify methods for overcoming processing shortcomings of PHB.
• To optimize fiber formation and material performance.

Main Methods:

• Screening of commercial PHB grades for morphology and rheology.
• Evaluation of meltblown process performance.
• Analysis of material degradation using rheological and SEC methods.
• Correlation of process temperature with complex shear viscosity.

Main Results:

• Significant variations in minimum melt temperature (175-200 °C) and throughput limitations observed.
• Achieved average fiber diameters as low as 2.4 μm, the finest reported.
• Broader initial molar mass distribution (>8) enhanced fiber formation stability and productivity.
• Longer polymer chains were more susceptible to degradation.

Conclusions:

• Complex shear viscosity can predict optimal processing temperatures for PHB.
• Broader molar mass distribution is key to overcoming PHB processing limitations.
• Optimized PHB processing yields finer fibers and improved thermal resistance.