Research on the Modification of Polyaspartic

For applications or environments with special requirements, the intrinsic properties of the material are often insufficient—such as thermal resistance at high temperatures or flexibility at low temperatures—so modification of the material is necessary. Current modification methods for Polyaspartic include resin modification, nanomodification, and other techniques.

Resin Modification

Resin modification introduces resin molecules into the Polyaspartic molecular structure through chemical means such as block or graft copolymerization. This approach is relatively simple and offers high yield. It is widely used to enhance the heat resistance of Polyaspartic, regulate reaction rates, and improve physical and mechanical properties.

A commonly used resin for modification is silicone resin. Polysiloxane possesses low surface energy, a low elastic modulus, excellent thermal stability, and oxidation resistance. Its backbone consists of alternating Si—O—Si bonds, giving it high flexibility. After silicone modification, the steric hindrance within the material increases, which limits the reaction between the modified material and –NCO groups. This prolongs the coating’s bonding time and significantly improves adhesion between the coating and substrate.

There are two main silicone modification methods: block modification and graft modification. Studies have shown that combining Polyaspartic and polysiloxane via block modification improves mechanical strength, impact resistance, and adhesion of the coating. Modified resins synthesized from 4,4'-diaminodicyclohexylmethane (H12MDA) and amino-terminated methoxysilane (KH-540) yield coatings with enhanced hardness, flexibility, tensile strength, and aging resistance; flexibility improves significantly at temperatures below 5 °C. Another method uses epoxy-terminated silicone compounds, introducing silicone into the polyurea chain through a ring-opening reaction. The resulting silicone-modified Polyaspartic, when cured with isocyanate hardener, demonstrates excellent hardness and impact resistance at both room and low temperatures.

Epoxy resin is also used for modification because of its excellent mechanical strength and electrical insulation. The epoxy molecular chains can disperse and interpenetrate the polyurea chains, forming a crosslinked network. Amino-terminated Polyaspartic polyurea (PUA) synthesized from Polyaspartic esters (PAEs) and isophorone diisocyanate (IPDI) can be toughened with epoxy resin. The flexible PUA chains intertwine with the cured epoxy network, enabling ductile deformation under stress and improving shear strength. When the ratio of PUA to epoxy resin is optimized, elongation at break and impact resistance increase significantly.

Nanomodification

Nanomodification is an effective method to introduce nanoparticles into Polyaspartic systems through the interaction between polyurea functional groups and active sites on the nanoparticle surface. Because nanomaterials exhibit unique surface and quantum size effects, their addition can enhance the strength of Polyaspartic materials.

A series of aliphatic polyureas synthesized via a two-step solution polymerization process were modified with nano-TiO₂ and amino-functionalized carbon nanotubes. The amino-functionalized carbon nanotubes covalently bonded to the polyurea chains, increasing crosslink density and thermal stability, as well as interfacial adhesion between the nanotubes and polyurea elastomer. Combining ultrasonic dispersion and high-speed mechanical stirring with silane coupling chemistry can also produce Polyaspartic nanocomposites. These modified materials show improved freeze resistance, carbonation resistance, and abrasion resistance.

Other Modification Methods

Besides resin and nanomodification, other approaches—such as fluorination and epoxidized soybean oil (ESO) modification—have been studied to further enhance hydrophobicity and thermal resistance.

Fluorine-containing materials have strong C–F bonds and high electronegativity, which protect the main molecular chain and endow materials with excellent surface and electrical properties, as well as strong hydrophobicity. Fluorinated Polyaspartic can be synthesized by reacting maleic anhydride and fluorinated alcohol with HDI trimer in the presence of a catalyst, using toluene as a dehydrating agent. During the conversion from primary to secondary amines, the –NH density decreases, while numerous fluorinated groups distributed along the polyether chains reduce the contact between –NH and –NCO groups, extending the reaction time. The resulting fluorinated Polyaspartic exhibits superior hydrophobicity, abrasion resistance, and chemical stability compared with the unmodified version.

Epoxidized soybean oil (ESO) contains 3–4 epoxy groups per molecule, which can undergo ring-opening reactions with amines under suitable conditions. ESO is inexpensive, abundant, thermally stable, and renewable. ESO can react with primary amines to form a mildly crosslinked network, improving the thermal stability of Polyaspartic. It has been found that reaction temperature affects the conversion of primary amines: because neighboring epoxy groups in the ESO chain create steric hindrance, higher temperatures accelerate the ring-opening reaction and increase conversion. This finding provides a theoretical foundation for ESO-modified Polyaspartic development.

Feiyang Protech has been specializing in the production of raw materials for polyaspartic coatings for 30 years and can provide polyaspartic resins, hardeners and coating formulations. Feel free to contact us: marketing@feiyang.com.cn

Our products list:

• Polyaspartic Resin
• Isocyanate Hardener
• Epoxy Hardener

Contact our technical team today to explore how Feiyang Protech’s advanced polyaspartic solutions can transform your coatings strategy. Contact our Tech Team