Irreversible transformations of native celluloses, upon exposure to elevated temperatures

Area of Science:

• Biopolymer Science
• Materials Science
• Plant Cell Wall Research

Background:

• Cellulose recalcitrance is often attributed to its native aggregated state.
• Isolation methods may alter cellulose structure, particularly at elevated temperatures.
• The impact of isolation temperature on cellulose's inherent properties is under-explored.

Purpose of the Study:

• To investigate the influence of elevated temperatures on isolated cellulose structure and accessibility.
• To determine if cellulose isolation conditions affect its assumed native state.
• To characterize the changes in cellulose properties due to thermal treatment.

Main Methods:

• Deuterium exchange was used to measure the accessibility of reactive sites in cellulose.
• Cellulose samples were isolated at ambient temperature and subsequently exposed to elevated temperatures.
• Changes in cellulose structure and accessibility were analyzed.

Main Results:

• Cellulose isolated at ambient temperature showed reduced accessibility to deuterium and probe molecules after thermal treatment.
• Elevated temperatures during isolation led to irreversible structural transformations.
• Isolated cellulose developed a polymeric semi-crystalline character.

Conclusions:

• The assumption that isolated cellulose retains its native state is challenged.
• Thermal processing significantly impacts cellulose's structural integrity and reactivity.
• Understanding these transformations is crucial for applications involving cellulose.