Novel Thermoplastic Cellulose Esters Containing Bulky Moieties and Soft Segments

Abstract

It is still challenging to convert cellulose into melt-processable materials because natural cellulose, which has a strong hydrogen bonding network, degrades before melting. Herein, a series of novel cellulose-based thermoplastics were successfully designed and fabricated by a simple and efficient homogeneous esterification of cellulose in an ionic liquid. Introducing ester substituents containing both bulky moieties and soft segments can improve the mobility of the cellulose chain, and the glass transition temperatures (T gs) appeared in the resultant cellulose esters. In particular, when the ester substituents consisted of bulky terminal moiety and soft middle segment, T gs of the corresponding cellulose esters were relatively low (80–160 °C), indicating these cellulose materials were suitable for melt processing. Accordingly, these thermoplastic cellulose esters can be processed into transparent disks, dumbbells, fibers and flexible films by traditional injection molding, melt extrusion, and hot pressing without any external plasticizers. Therefore, this work provides a simple and engineering method to construct melt-processable bioplastics from cellulose.

Direct one-step synthesis of a formally fully bio-based polymer from cellulose and cinnamon flavor

“…21 Recently, Zhang and co-workers have reported that cellulose phenylpropionate derivatives, which have a phenylpropionate unit similar to the structure of cinnamaldehyde, show thermoplasticity and are useful as plastics. 22 However, compared to classical esterification, oxidative esterification reactions are complicated and expected to result in side reactions due to the use of a powerful oxidizer. Furthermore, oxidative esterification has been considered unsuitable for the modification of poorly soluble cellulose in various solvents, including ionic liquids (ILs), 18,23 which are ionic compounds with melting points below 100°C, 24 because they require an excess of the alcohol to prevent the dimerization pathway of the aldehyde.…”

Cellulose Regeneration and Chemical Recycling: Closing the “Cellulose Gap” Using Environmentally Benign Solvents

“…[ 75 ] To improve these properties as well as processability, fatty acid esters are widely employed. [ 76 ] The hydrophobically modified surface led to significantly decreased water vapor, oxygen, nitrogen, and carbon dioxide permeability. [ 77 ] Surprisingly, cellulose films prepared from NaOH/urea or LiOH/urea solutions have even lower oxygen permeabilities than commercial oxygen barrier films such as poly(vinylidene chloride) and poly(vinyl alcohol).…”

Natural Polymers from Biomass Resources as Feedstocks for Thermoplastic Materials

“…Hydroxyl groups were esterified both with bulky and small substituents, resulting in a relatively low T g from 80 to 160 °C. The resulting materials can be used for common thermoplastic processing without external plasticization …”

“…The resulting materials can be used for common thermoplastic processing without external plasticization. [47] Besides esterification, cellulose ethers can also display thermoplastic properties. Via hydroxyl group substitution with alcohols, several derivatives such as methyl cellulose, carboxymethyl cellulose, and hydroxypropyl methylcellulose have been produced and commercialized.…”