News

Knowledge

Company News

Application Mind Map

Test Report

Technical Article

Industry News

How to test the chemical properties of UV 3D printing?

Release time:

2026-07-20 23:54

How to test the chemical properties of UV 3D printing?

UV‑3D‑printed parts are fabricated by layer‑by‑layer curing of liquid photopolymer resin under ultraviolet light, and their chemical properties directly affect the product’s safety, durability, and reliability. Unlike physical‑property testing, which focuses on mechanical strength and dimensional accuracy, chemical‑property evaluation emphasizes aspects such as the resin’s cure‑reaction kinetics, the level of uncured residual monomers, resistance to chemical attack, and the integrity of the crosslinked network. In high‑safety‑and‑durability‑critical applications—such as medical devices, dental prosthetics, and aerospace—chemical‑property testing is especially crucial. Each test is supported by standardized methods and dedicated instrumentation, together forming a comprehensive quality‑assessment framework.

I. Curing Reaction Characterization Testing

The curing reaction kinetics are a key metric for evaluating the printability and curing efficiency of photopolymer resins.

In situ UV–differential scanning calorimetry (UV‑DSC) is a precise analytical technique for characterizing the kinetics of curing reactions. By integrating an ultraviolet light source with a DSC instrument, this method enables simultaneous measurements under controlled UV irradiation within the sample cell, allowing accurate determination of key kinetic parameters such as the exothermic enthalpy of cure, reaction rate, and conversion degree. By systematically varying irradiance, temperature, wavelength, and exposure time, one can investigate how these variables influence curing kinetics, thereby providing a theoretical foundation for precisely optimizing layer‑by‑layer exposure times in additive manufacturing processes.

Critical exposure (Ec) and penetration depth (Dp) constitute another pair of core parameters that characterize the photopolymerization performance of resins. Ec denotes the minimum energy required to initiate the polymerization reaction, while Dp reflects the ultraviolet light’s ability to penetrate the resin. These two parameters directly influence the selection of exposure time and layer thickness during printing.

The evaluation of photopolymerization efficiency and conversion can be performed using real-time Fourier-transform infrared spectroscopy (RT‑FTIR). This method calculates conversion by monitoring, in real time, changes in the peak areas of characteristic double-bond absorptions during curing, enabling precise analysis of key parameters such as the curing rate, reaction activation energy, and the oxygen inhibition effect. Infrared spectroscopy can also detect alterations in functional groups within the resin, tracking the attenuation of characteristic absorption peaks corresponding to specific chemical bonds before and after curing.

II. Testing for Uncured Residues

The surface and interior of a printed model may retain uncured resin, which contains monomers, oligomers, photoinitiators, and other substances that can adversely affect the product’s mechanical strength, biocompatibility, and durability.

Monomer residue analysis is performed using gas chromatography–mass spectrometry (GC-MS), enabling both qualitative and quantitative determination of residual monomers and photoinitiator degradation products.

The concentration of volatile organic compounds (VOCs) is typically determined using thermogravimetric analysis (TGA) or gas chromatography (GC) to assess the low-molecular-weight substances that may be emitted from printed parts during storage and use.

The leaching test quantifies the levels of extractables by extracting the printed part in a specified solvent, serving as an important method for assessing the safety of medical and food-contact applications, and is often used in conjunction with ISO 10993 biocompatibility testing.

III. Chemical Resistance Testing

Chemical resistance assessment evaluates the ability of printed parts to withstand chemical exposure in real-world service environments.

The chemical immersion method involves immersing printed samples in chemicals such as acids, bases, organic solvents, or simulated body fluids; after a specified period, surface changes (discoloration, bubbling, softening) are observed, and the retention of mechanical properties is assessed.

Hydrolytic stability testing evaluates a material’s resistance to hydrolysis in humid environments, which is particularly critical for components subjected to prolonged exposure to moisture.

Oxidative stability testing evaluates a material’s resistance to oxidative degradation, while dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) can detect changes in performance before and after aging.

IV. Evaluation of Curing Degree and Crosslinking Density

Measurement of double-bond conversion is a direct method for assessing the degree of cure, employing real-time Fourier-transform infrared spectroscopy (RT‑FTIR) to monitor the attenuation of the characteristic absorption peak of the acrylate C=C double bond during the curing process. This assay enables optimization of the curing process, ensures product quality, and provides reliable data to support both research and development as well as manufacturing.

Gel content and swelling ratio measurements are essential methods for assessing the integrity of the crosslinked network. After curing, the sample is immersed in a specified solvent; its swollen mass and dry mass are weighed to calculate the gel content and swelling ratio, which provide insights into the crosslink density.

Thermogravimetric analysis (TGA) assesses the thermal stability and decomposition temperature of a resin by measuring its mass changes during heating, thereby providing an indirect indication of the thermal stability of the crosslinked network. Differential scanning calorimetry (DSC) can determine the glass transition temperature (Tg), which is closely related to the crosslink density.

V. Epoxide Equivalent and Component Analysis

For photosensitive epoxy resins, the determination of epoxy equivalent weight (EEW) is a critical analytical parameter for assessing the epoxy group content, directly influencing the resin’s reactivity, crosslinking density, and the mechanical properties of the final product. Common methods include titration—characterized by its simplicity and low cost—and spectroscopic techniques, such as infrared spectroscopy or nuclear magnetic resonance for qualitative and quantitative analysis.

Viscosity testing employs a rotational viscometer to measure the flow behavior of resins at various temperatures, serving as a fundamental metric for evaluating their processability and printability. pH testing is conducted to assess the acidity or alkalinity of the resin or rinse solution, ensuring it is non-corrosive.

VI. Conclusion

UV 3D printing chemical performance testing encompasses multiple dimensions, including curing reaction kinetics, uncured residues, chemical resistance, and the degree of cure and crosslink density. In-situ UV‑DSC and RT‑FTIR techniques precisely characterize curing kinetics and double-bond conversion; GC‑MS and VOC analysis ensure product safety and biocompatibility; chemical immersion and oxidation stability tests guarantee long-term reliability; gel content, TGA, and DSC provide quantitative evidence of crosslink network integrity; while fundamental parameters such as epoxy equivalent weight and viscosity furnish data to support formulation optimization. Chemical performance testing and physical performance testing complement each other, together forming a comprehensive quality evaluation framework for UV 3D‑printed products.

Disclaimer: The above content has been compiled from publicly available sources and is provided for reference only. If any infringement occurs, please contact us, and we will address it promptly.

Bosheng Related Product Recommendations – 3D Printing
Rigidity
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-100	Bisphenol A epoxy acrylate	High hardness, high gloss, excellent chemical resistance, and rich body.
B-113	Bisphenol A epoxy acrylate	High hardness, high gloss, high fullness, contains 20% TPGDA.
B-221	Aliphatic polyurethane acrylate	Fast curing, resistant to boiling water
B-276H	Aliphatic polyurethane acrylate	High hardness, fast curing, excellent toughness, and low yellowing.
B-296	Aliphatic polyurethane acrylate	Fast curing, chemical resistance, yellowing resistance, impact resistance
B-296M	Polyurethane acrylate	Fast curing, resistant to polar solvents, yellowing-resistant, and impact-resistant.
B-301	Aromatic polyurethane acrylate	Fast curing, excellent toughness, and good sandability.
B-302	Aromatic polyurethane acrylate	Fast curing, high strength, excellent toughness, and good grindability.
B-368	Aliphatic polyurethane acrylate	Good toughness, excellent leveling, excellent bend resistance, and excellent heat resistance.
B-529	Polyester acrylate	Excellent adhesion, low shrinkage, and good resin compatibility.
B-609	Aliphatic polyurethane acrylate	Fast curing, high hardness, scratch resistance, and chemical resistance.
Dentistry
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-100M	Bisphenol A epoxy acrylate	Low viscosity, high hardness, high gloss, and high body.
B-113	Bisphenol A epoxy acrylate	High hardness, high gloss, high fullness, contains 20% TPGDA.
B-276H	Aliphatic polyurethane acrylate	High hardness, fast curing, excellent toughness, and low yellowing.
B-296	Aliphatic polyurethane acrylate	Fast curing, chemical resistance, yellowing resistance, impact resistance
B-296M	Polyurethane acrylate	Fast curing, resistant to polar solvents, yellowing-resistant, and impact-resistant.
B-301	Aromatic polyurethane acrylate	Fast curing, excellent toughness, and good sandability.
B-302	Aromatic polyurethane acrylate	Fast curing, high strength, excellent toughness, and good grindability.
B-368	Aliphatic polyurethane acrylate	Good toughness, excellent leveling, excellent bend resistance, and excellent heat resistance.
B-376	Aliphatic polyurethane acrylate	LED yellowing is minimal, and the nail polish formulation exhibits excellent stability.
B-609	Aliphatic polyurethane acrylate	Fast curing, high hardness, scratch resistance, and chemical resistance.
B-79D	Polyester acrylate	High hardness, low yellowing, and high evaporation efficiency at elevated temperatures.
Casting
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-79D	Polyester acrylate	High hardness, low yellowing, and high evaporation efficiency at elevated temperatures.
Resilience
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-210D	Aliphatic polyurethane acrylate	Fast curing, low heat of reaction, and excellent toughness.
B-286	Aliphatic polyurethane acrylate	Low heat generation, excellent toughness, wear resistance, and impact resistance.
B-296M	Polyurethane acrylate	Fast curing, resistant to polar solvents, yellowing-resistant, and impact-resistant.
Elasticity
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-268M	Aliphatic polyurethane acrylate	Good flexibility, excellent adhesion, superior plating performance, and strong hiding power.
B-296	Aliphatic polyurethane acrylate	Fast curing, chemical resistance, yellowing resistance, impact resistance
B-39	Aliphatic polyurethane acrylate	Low viscosity, good flexibility, and low volatility.
B-450-2	Aliphatic polyurethane acrylate	Low shrinkage upon curing, excellent flexibility, and good tensile strength and elasticity.
B-451	Aliphatic polyurethane methacrylate	Good stretchability, low shrinkage, and excellent flexibility.
High transparency
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-296	Aliphatic polyurethane acrylate	Fast curing, chemical resistance, yellowing resistance, impact resistance
B-376	Aliphatic polyurethane acrylate	LED yellowing is minimal, and the nail polish formulation exhibits excellent stability.
Environmental protection
Product Model/English Abbreviation	Product Name/Product Type	Product Features
B-296SW	Aliphatic polyurethane acrylate	Yellowing resistance, impact resistance, bio-based content > 40%
Monomer Recommendation
Product Model/English Abbreviation	Product Name/Product Type	Product Features
BM1211 (HPMA)	Hydroxypropyl methacrylate	HEMA-free, high strength, low irritation, and high adhesion
BM2223 (TPGDA)	Di(propylene glycol) diacrylate	Good flexibility and low volatility
BM3231 (TMPTA)	Trimethylolpropane triacrylate	High crosslink density, high hardness, high gloss, and excellent wear resistance.
BM3235 (PET3A)	Pentaerythritol triacrylate	Fast curing, high crosslink density, high hardness, and excellent chemical resistance.
BM3380 (3EO-TMPTA)	Pentaerythritol triacrylate	More flexible and less irritating than TMPTA.

Share to:

Detailed Overview of UV 3D Printing Technology Types (Part 1)

How to test the physical properties of UV 3D printing?