@article {48389, title = {Biodegradable, solvent-free photocrosslinkable PLLA resin formulations for additive manufacturing}, journal = {Macromolecular Chemistry and Physics}, volume = {223}, year = {2022}, month = {NOV}, type = {Article}, abstract = {

Acrylate end-functionalized linear and star poly l-lactide (PLLA) based aliphatic, photocurable oligomeric crosslinkers are developed, which are formulated with hydroxyl (ethyl)methacrylate (HEMA) as a biodegradable reactive diluent to demonstrate successful application for solvent-less 3D printing using digital light processing (DLP) technique as well as a custom-designed direct ink writing 3D printer. The resin formulation for 3D printing is optimized using spot curing, photodifferential scanning calorimetry and cure depth analysis. The 3D printed parts exhibit promising mechanical property along with improved hydrophilicity and biodegradability. The development of new photocurable resin formulations are expected to meet the growing demand for raw materials that can be applied for developing custom designed bio implantable objects.

}, keywords = {3D printing, biodegradable materials, digital light processing, L-Lactide, photocurable materials}, issn = {1022-1352}, doi = {10.1002/macp.202200139}, author = {Pal, Shibam and Asha, S. K.} } @article {48303, title = {Design and synthesis of photocrosslinker and light blocker based on L-Amino acid polyester and their application in solvent-free resin formulation for DLP/SLA 3D printing}, journal = {Polymers}, volume = {270}, year = {2023}, month = {MAR }, pages = {125781}, type = {Article}, abstract = {

Customising material design for new technological applications like additive manufacturing (AM) is a challenging yet promising approach to create a palette of materials suitable for developing eco-friendly products. LGlutamic acid and L-aspartic acid based aliphatic, photocurable polyester crosslinkers were designed and developed and incorporated into a solvent-free photocurable resin formulation with hydroxyl (ethyl)methacrylate (HEMA). Proof-of-concept 3D printing of clear and transparent objects was demonstrated using digital light processing (DLP) and Stereolithography (SLA) techniques. Resolution of the 3D printed objects could be improved by incorporating a Dansyl labelled L-glutamic acid polyester, which not only aided in modulating the viscosity of the resin formulation but could also function as a light blocker, thereby avoiding polymerization of unwanted areas while 3D printing. The curing kinetics of the photocurable formulation was analyzed using photo differential Scanning Calorimetry. Enzymatic degradability studies of 3D printed films were undertaken in PBS buffer containing esterase enzyme and compared with 3D printed samples using HEMA and a commercial crosslinker (Trimethylolpropane triacrylate (TMPTA)). Scanning electron microscopy (SEM) was used to evaluate the morphology of the 3D printed films before and after enzymatic degradation in the PBS buffer for 60 days. The 3D printed amino acid crosslinked films of HEMA presented high degree of degradation in contrast to the near total absence of any degradation in the 3D printed film crosslinked using TMPTA. The availability of new photocurable formulations that are enzymatically degradable are highly sought after for 3D printing applications.

}, keywords = {3D printing, Crosslinker, L -Amino acid Polyester, Light blocker, Photocurable}, issn = {0032-3861}, doi = {10.1016/j.polymer.2023.125781}, author = {Kamble, Ganesh N. and Joshi, Dheeraj Chandra and Asha, S. K.} } @article {49039, title = {Thiol-ene-based degradable 3D printed network from bio resource derived monomers ethyl-lactate and isosorbide}, journal = {European Polymer Journal}, volume = {205}, year = {2024}, month = {FEB }, type = {Article}, abstract = {

A polymeric ene-based thiol-ene network is reported that was demonstrated for light-based 3D printing. Allyl poly (acrylate ethyl lactate) (PAEL) was synthesized starting from ethyl lactate in an efficient and scalable manner. Ethyl lactate is a biobased material obtained naturally or chemically in high yields in the form of ethyl ester of lactic acid. Isosorbide, which is also a bio based resource was converted into thiol derivative and was used along with Pentaerythritol tetrakis(3-mercaptopropionate) (PETMP) as multifunctional thiol. The polymeric nature of the ene (i.e. PAEL) imparted exceptionally high mechanical properties like Young{\textquoteright}s modulus of 1.75 GPa as well as high thermal stability with a decomposition temperature (Td,10\%) exceeding 350 C for all the networks studied. The properties could also be customized by fine tuning the type and stoichiometric ratio of the thiol crosslinked employed. For instance, the Young{\textquoteright}s modulus range from 1.75 GPa to 1.03 GPa and glass transition temperature range from 44 C to 54 C could be achieved. DLP 3D printing was used to demonstrate the printability of the resins with high resolution and structural fidelity. The study also highlights the basemediated rapid hydrolytic degradation efficiency of the 3D printed parts, demonstrating the applicability of these novel polymeric ene based thiol-ene for sustainable and eco-friendly 3D printable formulations.

}, keywords = {3D printing, Degradation, digital light processing, Poly (acrylate ethyl lactate), Thiol-ene}, issn = {0014-3057}, doi = {10.1016/j.eurpolymj.2024.112761}, author = {Pal, Shibam and Asha, S. K.} }