Stereolithography (Vat polymerization)
Photopolymer resin property analysis for 3D printing
To create 3D models and prototypes quickly and flexibly, many additive manufacturers use stereolithography (SLA), also known as Vat Polymerization. Indeed, it’s the oldest additive manufacturing or 3D printing technology. Widely used for creating polymeric prototypes, it is now also finding applications in final part production. Stereolithography employs a vat of photopolymer resin, which is selectively cured using Ultraviolet (UV) or Visible (Vis) light, while a support platform moves the cured object upwards or downwards layer by layer.
To achieve the best properties in the final cured material, the characteristics of the oligomers within the photopolymer resin must be optimized. To support additive manufacturers with this, Malvern Panalytical offers an effective material characterization solution.
Why is material characterization important?
Stereolithography uses photopolymer formulations comprising oligomers, monomers, and photoinitiators that cross-link on exposure to UV or Visible light. The properties of the final cured material, such as its modulus and chemical properties, are influenced by the molecular weight distribution and molecular structure of the oligomers, and the proportion of photoinitiator used. These properties also affect the rheology and viscosity of the photopolymer formulation. To optimize the chemical properties of the final cured material, it’s therefore very important for additive manufacturers to analyze and control the oligomers’ molecular weight distribution and structure.
How can Malvern Panalytical’s solutions help?
To enable additive manufacturers to analyze and optimize molecular weight distribution and structure in photopolymer resins, Malvern Panalytical offers a Gel Permeation Chromatography (GPC) solution with advanced multi-detection through its Omnisec platform. The Omnisec combines refractive index (RI), right- and low-angle light scattering detectors (RALS and LALS), and a differential viscometer to give detailed information on absolute molecular weight and molecular structure, such as branching. The Omnisec is ideal for analyzing low-molecular-weight resins and oligomers – down to 200 g/mol. What’s more, it can also measure low concentrations of material, making it ideal for analyzing newly synthesized polymers that are available in limited volumes.
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