Biodegradable poly(vinyl alcohol) foams supported by cellulose nanofibrils: processing, structure, and properties

Area of Science:

• Materials Science
• Polymer Science
• Biomaterials Engineering

Background:

• Growing demand for sustainable materials necessitates biodegradable alternatives to conventional plastics.
• Poly(vinyl alcohol) (PVA) is a water-soluble polymer with potential for foam applications.
• Cellulose nanofibrils (CNF) offer excellent mechanical properties and biodegradability.

Purpose of the Study:

• To develop biodegradable composite foams using PVA and CNF via freeze-drying.
• To investigate the impact of CNF content, solid content, and quenching temperature on foam properties.
• To evaluate the mechanical performance, water resistance, and biodegradation of the composite foams.

Main Methods:

• Unidirectional freeze-drying technology for foam fabrication.
• Scanning electron microscopy (SEM) for microstructure analysis.
• Compressive testing, X-ray diffraction (XRD), water uptake, and biodegradation tests for property evaluation.

Main Results:

• Incorporation of 30 wt% CNF significantly enhanced mechanical strength, modulus, energy absorption, and water resistance.
• CNF addition led to regular and compact pore structures, improving dimensional stability.
• Biodegradation tests in simulated aerobic compost showed accelerated degradation with CNF presence.

Conclusions:

• PVA/CNF composite foams exhibit tunable properties and enhanced performance through controlled freeze-drying and composition.
• The study provides valuable insights into creating biomimetic cellular foams with desirable mechanical and environmental characteristics.
• CNF incorporation is a promising strategy to improve both the performance and biodegradability of PVA-based foams.