Investigation of surface morphology of cellulose acetate micro-mould after deacetylation

Abstract

Biodegradable honeycomb patterns are useful for a cell culture substrate and tissue engineering. Attaining control over pore size and depth is extremely important for many biological and optical applications. In this study, uniform sizes and various heights of cellulose acetate (CA) honeycomb patterns were fabricated using a photoresist micro-mould. The carbonyl peak was diminished by 60%, 90% and 98% after 1 h, 4 h and 7 h of deacetylation (DA) reaction, respectively, and disappeared after 31 h of DA reaction. The UV–visible transmittance decreased as the DA reaction time increased up to 17 h and increased after 60 h reaction. The transmittance reduction was due to the rough structure of the surface and the inside of the pattern created during the early DA reaction. The rough structure became dense and smooth as the reaction time further increased. This may be a result of uniform removal of the acetyl group at the surface and inside the film after enough time of DA reaction. The line width was increased by 39% and 56% after 1.5 h and 17 h DA reaction, respectively. The line width returned to the initial width after further DA reaction. These results imply that the structure of the CA mould became rough in the early stage of the DA reaction and became dense and smooth after further DA reaction.

Preparation and Characterization of Hollow Fiber Carbon Membranes from Cellulose Acetate Precursors

“…The peaks at 1700-1800, 1350-1400, 1200-1300, and 1000-1150 cm -1 attributed to the carbonyl vibration (-CdO), methyl deformations, acetyl stretching (CH 3 CO-), and C-O stretching, respectively. 23 It is found that the intensities of the characteristic absorption peaks for the acetyl group (CH 3 CO-) decreased following the prolonging of the reaction time, but the absorption peak at 3400 cm -1 (-OH) became broader as the reaction time increased compared to those of the original CA membranes. This result indicates that the number of -OH groups increases as the reaction time increases due to the conversion of cellulose acetate to cellulose gradually (CH 3 CO-was substituted by -OH).…”

“…Figure shows the FTIR spectra for the CA hollow fiber membranes and the deacetylated membranes with 0.075 M NaOH in 96% ethanol solution for different times. The peaks at 1700−1800, 1350−1400, 1200−1300, and 1000−1150 cm −1 attributed to the carbonyl vibration (−CO), methyl deformations, acetyl stretching (CH 3 CO−), and C−O stretching, respectively . It is found that the intensities of the characteristic absorption peaks for the acetyl group (CH 3 CO−) decreased following the prolonging of the reaction time, but the absorption peak at 3400 cm −1 (−OH) became broader as the reaction time increased compared to those of the original CA membranes.…”

Deacetylation of cellulose acetate nanofibers by fluorination for carbon nanofibers

“…The first step is slow and reversible, whereas the other two steps are fast and irreversible. In the final step, the CA nanofiber attains a similar chemical structure to that of cellulose through removal of the acetyl groups [7]. The introduction of four additional CF bond is considered from random attack by fluorine radicals at the other carbon positions in the CA nanofiber [13].…”

“…However, CA requires deacetylation process for the preparation of CFs because CA melts during the carbonization process. The deacetylation of CA is usually performed through a hydrolysis method using alkoxide, acidic or alkali solutions [6,7]. However, these methods have disadvantages such as complex procedures, long reaction time, extreme pH levels and substantial amounts of water for washing.…”

Kinetic Analysis of Cellulose Acetate/Cellulose II Hybrid Fiber Formation by Alkaline Hydrolysis

“…The demand for cellulose and its derivatives within the technical textile industry is high due to its outstanding properties, such as excellent moisture absorption, good abrasion resistance, and high strength. However, native cellulose (cellulose Iβ) has poor solubility in most solvents as a result of extensive hydrogen bonding between molecular chains, which forms a supramolecular structure that can be described by a two-phase model with regions of high orientation (crystalline) and low orientation (amorphous). − This greatly restricts the development and utilization of cellulose and hence cellulose derivatives have been developed for use in fiber applications.…”