How Acrylic Additives Are Transforming PVC 3D Printing

Acrylic additives are rewriting the rules of 3D printing, turning brittle PVC layers into unbreakable bonds.

The plastics industry is on the verge of a materials revolution. Researchers are solving one of additive manufacturing’s biggest challenges: achieving strong interlayer adhesion in 3D-printed thermoplastics. At ANTEC® 2025, Dr. Manoj Nerkar from Dow Inc. presented groundbreaking research on specialized acrylic processing aids. These additives improve the printability and performance of PVC in fused deposition modeling (FDM).

You can also read: Inside Materials – PVC

Global Solutions for Local Challenges

Dow’s research leverages a global network of expertise, with regional manufacturing and R&D hubs in the U.S. (Louisville, Collegeville), Europe (Luxembourg), and Asia (Singapore, Shanghai). This infrastructure ensures rapid development and deployment of tailored acrylic additives like PARALOID™, which are already optimized for diverse polymer systems, including:

• Engineering thermoplastics (PC/ABS, PEEK)
• Commodity resins (PVC, HDPE)
• Bio-based polymers (via PARALOID™ BPW series)

The additives’ versatility stems from their core chemistry: high molecular weight MMA copolymers produced via emulsion polymerization, designed to balance thermal stability (Tg >100°C) and miscibility with PVC.

The Fundamental Challenge of Layer Bonding 

Unlike traditional manufacturing methods that produce uniform structures, FDM 3D printing builds objects by depositing molten polymer strands one layer at a time. This method creates weak spots at the layer boundaries because rapid cooling and the polymer’s rheological properties restrict molecular diffusion and entanglement. In PVC, a material with a notoriously narrow processing window. thermal sensitivity and prolonged heat exposure further intensify these issues.

Dr. Nerkar’s research shows that poor interlayer adhesion results from limited polymer chain mobility during the crucial bonding phase. When the printer deposits each layer, the brief thermal contact period prevents sufficient molecular interpenetration. This limitation produces parts with mechanical anisotropy, with Z-axis strength dropping 50–70% compared to the X–Y plane, a critical problem for functional applications.

Acrylic Additives: The Molecular Architects 

Dow’s solution leverages the unique properties of high molecular weight MMA copolymers from their PARALOID™ additive series. These specialized acrylic processing aids function as molecular architects within the PVC matrix through several synergistic mechanisms.

The additives’ high glass transition temperature creates a miscible blend with PVC, while their extended polymer chains function as physical bridges between PVC molecules. During processing, these acrylic chains enhance shear-induced crystallization, a phenomenon where mechanical energy transforms the polymer’s amorphous regions into ordered structures. This is particularly crucial for PVC, which requires precise thermal and shear conditions to achieve optimal fusion.

Laboratory rheometer studies demonstrated this effect dramatically. At 170°C with 2 PHR loading, acrylic-modified PVC formulations reached complete fusion in under three minutes at 45 RPM, compared to prolonged times for unmodified PVC. Increasing rotor speed to 65 RPM to simulate higher shear conditions in printer nozzles further accelerated fusion by 30-40%, proving the additives’ shear-thickening behavior.

From Lab to Printer

Transitioning from controlled lab experiments to actual 3D printing revealed the harsh realities of PVC processing. Initial attempts using standard PVC filaments at 175-185°C resulted in catastrophic nozzle clogging and “mouse bite” defects, a phenomenon where incomplete layer bonding causes material to tear during deposition.

The research team tackled these issues with an iterative optimization process. They tried increasing the temperature to 200–230°C, which initially seemed promising. However, the higher temperatures caused new problems. PVC degraded when exposed to temperatures above 180°C, leading to dark discoloration and blocked extruders that required disassembly for cleaning.

The solution emerged through careful formulation and process optimization. Incorporating 4 PHR of PARALOID™ K-175 alongside optimized stabilizers, the team achieved stable extrusion at 210°C, which stays below PVC’s degradation threshold while ensuring proper flow. They adjusted the printer parameters to deposition speeds of 30 mm/s and 90 mm/s, and a layer height of 0.4 mm, ensuring sufficient time for interlayer diffusion while maintaining dimensional accuracy.

Quantifying Performance Gains 

The mechanical testing evaluated distinct orientation configurations to fully characterize the 3D printed PVC’s anisotropic behavior. Specimens were prepared in X-Y and Z directions, with dogbone samples punched either parallel or perpendicular to the print lines. Acrylic processing additives significantly improved elongation at break in the direction perpendicular to printing layers, increasing ductility from ~6–10% (control) to ~7–12%. Moreover, specimens showed a 360% increase in yield load (from 9.3 lbf to 43.6 lbf) with 4 PHR additive loading. This confirms their critical role in enhancing interlayer adhesion, the primary failure point in 3D-printed PVC.

Looking Ahead 

This research brings clear, real-world benefits. Manufacturers can harness PVC’s cost-effectiveness and chemical resistance to push the boundaries of 3D printing. They can create high-performance components for medical devices, automotive parts, and intricately designed piping for construction. Moreover, consumer goods makers gain new freedom to design durable, technically advanced products.

Dow’s team is exploring several promising directions. One is developing acrylic additives for flexible PVC, which is harder to process due to plasticizer migration. Another focus is scaling the technology for industrial pellet extrusion systems that print large structural parts. The most intriguing effort is early work on multi-material printing, where acrylic additives could improve adhesion between different polymers in hybrid structures.