This study was supported by GreenPAC Polymer Application Centre as part of Project 140413: &#34;3D Printing in Production&#34;.&#160;We would like to acknowledge Albert Hartman, Corinne van Noordenne, Rens van Leeuwen, Anniek Bruins, Femke Tamminga, Jur van Dijken and Albert Woortman for facilitating the video shooting.

CAUTION: Please consult all relevant material safety data sheets (MSDS) before use.
1. Preparation of Photocurable Resin
NOTE: Please use personal protective equipment (safety glasses, gloves, lab coat) during the following procedure. See our previous work12 for more details on this section.
<ol>
	<li>Pour 50 g of 1,10-decanediol diacrylate (SA5201) in a 500 mL Erlenmeyer flask.</li>
	<li>Add 1.0 g of diphenyl(2,4,6-trimethylbenzoyl)phosphi...

<ol>
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C., Schwentenwein, M., Gorsche, C., Stampfl, J., Liska, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toughening+of+photo-curable+polymer+networks:+A+review.">Toughening of photo-curable polymer networks: A review.</a> Polymer Chemistry. 7, 257-286 (2016).</li><li>Miao, S., Zhu, W., Castro, N. J., Nowicki, M., Zhou, X., Cui, H., Fisher, J. P., Zhang, L. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=4D+printing+smart+biomedical+scaffolds+with+novel+soybean+oil+epoxidized+acrylate.">4D printing smart biomedical scaffolds with novel soybean oil epoxidized acrylate.</a> Scientific Reports. 6, 27226 (2016).</li><li>Voet, V. S. D., Strating, T., Schnelting, G. H. M., Dijkstra, P., Tietema, M., Xu, J., Woortman, A. J. 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C., Liska, R., Stampfl, J., Gurr, M., M&#252;lhaupt, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymers+for+3D+Printing+and+Customized+Additive+Manufacturing.">Polymers for 3D Printing and Customized Additive Manufacturing.</a> Chemical Reviews. 117, 10212-10290 (2017).</li><li>Weng, Z., Zhou, Y., Lin, W., Senthil, T., Wu, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure-property+relationship+of+nano+enhanced+stereolithography+resin+for+desktop+SLA+3D+printer.">Structure-property relationship of nano enhanced stereolithography resin for desktop SLA 3D printer.</a> Composites: Part A. 88, 234-242 (2016).</li><li>Scalera, F., Esposito Corcione, C., Montagna, F., Sannino, A., Maffezzoli, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+characterization+of+UV+curable+epoxy/hydroxyapatite+suspensions+for+stereolithography+applied+to+bone+tissue+engineering.">Development and characterization of UV curable epoxy/hydroxyapatite suspensions for stereolithography applied to bone tissue engineering.</a> Ceramics International. 40, 15455-15462 (2014).</li><li>Lee, H., Fang, N. 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(128), e56340 (2017).</li><li>Decker, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Light-induced+crosslinking+polymerization.">Light-induced crosslinking polymerization.</a> Polymer International. 51, 1141-1150 (2002).</li><li>Elliot, J. E., Bowman, C. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Predicting+network+formation+of+free+radical+polymerization+of+multifunctional+monomers.">Predicting network formation of free radical polymerization of multifunctional monomers.</a> Polymer Reaction Engineering. 10, 1-19 (2002).</li><li>Ellakwa, A., Cho, N., Lee, I. 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Additive manufacturing is applied in fabrication of tailor-made prototypes and small series, when the higher production costs per part can compete with conventional processes since there is no need for production of molds and tools. In the last decade, the revenues from services and products related to additive manufacturing have grown exponentially13. The largest fraction of material sales is from photopolymers. The growth attracted attention and initiated the investments of major industries, <em...

Rapid prototyping enables on-demand production and design freedom and allows the efficient manufacturing of 3D constructs in a layer-by-layer manner1. As a result, 3D printing as a fabrication technique has developed rapidly in recent years2. Various technologies are available, all relying on the translation of virtual models into physical objects, and applying processes such as extrusion, direct energy deposition, powder solidification, sheet lamination and photopolymerization. The latter involves stepwise UV curing of liquid photopolymer resins. In 1986, Hull and co-workers developed the stereolithography apparatus (SLA), a UV laser-based 3D printer. More recently, a similar process called digital light processing (DLP) has become available, in which photopolymerization is initiated by a light projector. Together, DLP and SLA are referred to as stereolithography 3D printing3.
SLA is applied in high-resolution prototyping and fabrication of biomedical devices4,5. This technology is superior to the widely used fused deposition modeling (FDM) in terms of accuracy, surface finishing and resolution6. Depending on the architecture of the product, a support structure is integrated in the 3D model to stabilize the construct during fabrication. Furthermore, a post-printing treatment of manufactured parts is required7,8. Typically, printed objects are washed in an alcohol bath to dissolve unreacted resin, and subsequent curing in an UV oven is performed to guarantee full conversion of the polymerization9.
In general, resins for lithography-based additive manufacturing rely on photocurable systems containing multifunctional acrylates or epoxides10. Current photopolymer resins on the commercial market are fossil-based and expensive, while the availability of low-cost renewable resins is needed to facilitate waste-free and local manufacturing of sustainable 3D products for a biobased economy1,6. Recently, photopolymer resins based on renewable acrylates were developed and successfully applied in stereolithography 3D printing11,12. In this detailed protocol, we demonstrate the rapid prototyping with biobased resins on a commercial stereolithography apparatus. Special attention is paid to critical steps in the procedure, i.e., resin formulation and post-printing treatments, to help new practitioners in the field of additive manufacturing.

<table>
	<tbody>
		<tr>
			<td>Isobornyl acrylate&#160;</td>
			<td>Sartomer</td>
			<td>SA5102</td>
			<td>Acrylate monomer</td>
		</tr>
		<tr>
			<td>1,10-decanediol diacrylate</td>
			<td>Sartomer</td>
			<td>SA5201</td>
			<td>Acrylate monomer</td>
		</tr>
		<tr>
			<td>Pentaerythritol tetraacrylate</td>
			<td>Sartomer</td>
			<td>SA5400</td>
			<td>Acrylate monomer</td>
		</tr>
		<tr>
			<td>Multifunctional epoxy acrylate</td>
			<td>Sartomer</td>
			<td>SA7101</td>
			<td>Acrylate oligomer</td>
		</tr>
		<tr>
			<td>Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TPO), 97%</td>
			<td>Sigma Aldrich</td>
			<td>415952</td>
			<td>Photoinitiator</td>
		</tr>
		<tr>
			<td>2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene (BBOT), 99%</td>
			<td>Sigma Aldrich</td>
			<td>223999</td>
			<td>Optical absorber</td>
		</tr>
		<tr>
			<td>Isopropyl alcohol (IPA), 99%</td>
			<td>Bleko</td>
			<td>1010500</td>
			<td>For alcohol bath (applied in Form Wash)</td>
		</tr>
		<tr>
			<td>Paar Physica MCR300&#160;</td>
			<td>Anton Paar</td>
			<td>-</td>
			<td>Rheometer with parallel plate geometry</td>
		</tr>
		<tr>
			<td>Form 2 Printer</td>
			<td>Formlabs</td>
			<td>-</td>
			<td>Desktop SLA 3D printer</td>
		</tr>
		<tr>
			<td>Form Wash&#160;</td>
			<td>Formlabs</td>
			<td>-</td>
			<td>Washing station</td>
		</tr>
		<tr>
			<td>Form Cure</td>
			<td>Formlabs</td>
			<td>-</td>
			<td>UV oven</td>
		</tr>
		<tr>
			<td>Instron 4301 1KN Series IX</td>
			<td>Instron</td>
			<td>-</td>
			<td>Universal testing machine</td>
		</tr>
		<tr>
			<td>Philips XL30 ESEM-FEG&#160;</td>
			<td>Philips</td>
			<td>-</td>
			<td>Scanning electron microscope</td>
		</tr>
	</tbody>
</table>

stereolithographic 3d printing with renewable acrylates

The accessibility of cost-competitive renewable materials and their application in additive manufacturing is essential for an efficient biobased economy. We demonstrate the rapid prototyping of sustainable resins using a stereolithographic 3D printer. Resin formulation takes place by straightforward mixing of biobased acrylate monomers and oligomers with a photoinitiatior and optical absorber. Resin viscosity is controlled by the monomer to oligomer ratio and is determined as a function of shear rate by a rheometer with parallel plate geometry. A stereolithographic apparatus charged with the biobased resins is employed to produce complex shaped prototypes with high accuracy. The products require a post-treatment, including alcohol rinsing and UV irradiation, to ensure complete curing. The high feature resolution and excellent surface finishing of the prototypes is revealed by scanning electron microscopy.

Four representative resin compositions are displayed in Table 1, along with their average biobased carbon content (BC) derived from the individual BC of the components. The resin viscosity (Figure 1) is influenced by the ratio of acrylate monomers and oligomers and typically demonstrates Newtonian behavior. The mechanical properties of parts manufactured from various resins were determined by stress-strain analysis. Figur...

Watch this Scientific Journal Video about Stereolithographic 3D Printing with Renewable Acrylates at JoVE.com

Stereolithographic 3D Printing with Renewable Acrylates

A protocol for additive manufacturing with renewable photopolymer resins on a stereolithography apparatus is presented.

The accessibility of cost-competitive renewable materials and their application in additive manufacturing is essential for an efficient biobased economy. ...

This method can help to understand key subjects in the field of of additive manufacturing, such as resin formulation and post-printing treatment. The main advantage of this technique is that it enables the accurate and on-demand fabrication of sustainable products. This method will provide insight into laser-based stereolithography but it can also be applied to other 3D printing techniques such as Digital Light Processing.To begin, pour 50 grams of 1, 10-decanediol diacrylate in a 500-milliliter Erlenmeyer flask. Add 1.0 grams of TPO and 0.40 grams of BBOT to the flask. Equip the Erlenmeyer flask with a mechanical stirrer and stir the mixture at 200 rpm for five minutes at room temperature in order to dissolve the TPO and BBOT in the acrylate monomer.Add 100 grams of pentaerythritrol tetraacrylate and 100 grams of multi-functional epoxy acrylate to the mixture. Now stir the mixture at 200 rpm for 30 minutes at 50 degrees Celsius to ensure a homogeneous resin. Remove the mechanical stirrer and fit the flask with a stopper.Wrap the flask in aluminum foil to protect the biobased acrylate photopolymer resin from light. Now cover the bottom plate of a rheometer characterized by parallel-plate geometry with the photoresin. Set the gap between the plates at one millimeter and cover the rheometer with a UV-resistant hood.Measure the resin viscosity at room temperature at shear rates from 0.1 to 100 inverse seconds. Turn on the the SLA 3D printer and select the Open mode. Depending on the architecture of the product, a support structure can be integrated in the 3D model to stabilize the construct during fabrication.Start the model preparation software on a computer. To choose the desired print settings, select Clear for material, Version V4, and 50-micron layer thickness. Open the digital model of the complex-shaped prototype which is a standard tesselation language file, then choose the location and orientation on the build platform.Upload the print job to the SLA 3D printer. Now pour 200 milliliters of the biobased photoresin into a resin tank. Open the 3D printer and mount the resin tank properly.Mount the build platform and close the 3D printer. Following preparation of the 3D printer, start the print job. Allow the 3D printer to fabricate complex-shaped prototypes.Do not open the printer until the print job is finished. For the demonstrated protocol, the wavelength of the UV laser is 405 nanometers. The print time of the object is 2.5 hours and is shown here in fast motion.When the print job is finished, open the printer. Remove the build platform with the produced parts attached and close the printer. Open the washing station filled with isopropyl alcohol and insert the build platform.Start the procedure and rinse for 20 minutes to remove any unreacted resin. When the rinsing procedure is finished, remove the build platform from the washing station and detach the prototypes from the build platform. Allow the prototypes to air dry for 30 minutes.In the meantime, preheat the UV oven at 60 degrees Celsius. Open the UV oven and quickly place the prototypes on the rotating platform. Close the UV oven and cure for 60 minutes at 60 degrees Celsius to ensure complete conversion.When the post-curing procedure is finished, open the UV oven and take out the prototypes. To characterize the surface morphology of complex-shaped prototypes, cut approximately one centimeter of internal helix from the complex-shaped prototype using a razor blade. Attach the sample to the sample holder with double-sided, carbon-conductive tape.Prior to imaging, coat the sample with 30 nanometers of platinum palladium on a sputtering system. Now insert the sample into a scanning electron microscope operating at an accelerating voltage of five kilovolts. Acquire several images of the sample at 30X and 120X magnification.The viscosity of the renewable resin is an essential parameter in the 3D printing process and is controlled by the monomer to oligomer ratio. Typically a shear rate of 100 inverse seconds is achieved during the recoat of liquid resin in the printing process. All bioresins have a viscosity below five Pascal seconds and are appropriate for application in stereolithographic printing equipment.Shown here are representative results for the mechanical behavior of the objects printed from various bioresins, including tensile strength and e-modulus. However, optimization of the post-printing treatment by varying the duration of washing, drying, curing, and temperature of curing can lead to a significant improvement in mechanical performance. The smooth surface and high feature resolution of the complex-shaped prototypes is revealed by the electron microscope.The serrated vertical edges of the helices arise from the layer-by-layer SLA printing process, in which the top of an exposed layer receives a larger UV dose compared to the back of a layer. The extent of surface cracking is related to the initial resin viscosity. After its development, this technique paved the way for application of cost-competitive bioresins to facilitate waste-free and local manufacturing of sustainable products.Don't forget that working with acrylates can be hazardous. Precautions such as wearing safety glasses and gloves should always be taken while performing this procedure.

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Chemistry

9.4K ビュー.  NHL Stenden University of Applied Sciences. This method can help to understand key subjects in the field of of additive manufacturing, such as resin formulation and post-printing treatment. The main advantage of this technique is that it enables the accurate and on-demand fabrication of sustainable products. This method will provide insight into laser-based stereolithography but it can also be applied to other 3D printing techniques such as Digital Light Processing.To begin, pour 50 grams of 1, 10-decanediol diacrylate in a 500-...