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Polymer Stabilization for Electric Vehicles

The SI Group is the leading manufacturer of chemical antioxidants, stabilizers, compatibilizers, and coupling-agent technology among major automotive manufacturers. With current demand and popularity, the electric vehicle (EV) market has seen tremendous growth in R&D efforts from OEMs looking to electrify the majority of their fleets.
The next generation of electric vehicles needs to provide long-term performance and handle various environmental stresses from internal and external forces. Polymer stabilizers improve EV technology and auto components by providing internal protection while maintaining physical and surface properties. With exposure to higher thermal temperatures from the lithium-ion battery engine, polymer systems must protect the powertrain and the consumer while maintaining operational capabilities. 


Vehicle polymer degradation can lead to odor, increased harsh sounds, fogging, color fading, and VOC emissions. Polymer degradation is caused by exposure to volatile thermal temperatures, ultra-violet light, and extreme weather environments. The SI Group polymer technology of antioxidants, secondary antioxidants, UV stabilizers, and coupling agents protect EV automotive components from polymer degradation. Furthermore, external environments such as carbon pollution from combustion engine vehicles can accelerate polymer degradation in the exterior auto components. Thermal degradation can be visible in the exterior elements of the car, like cracking, reduced strength, decreased flexibility or stiffness, and overall discoloration of the polymer system. 



The auto industry faces a demand increase for plastic components required for electric and autonomous vehicles. In contrast, combustion engine vehicles will see a decline in orders for polymer components such as fuel lines and air intake pipes. This new opportunity to evolve EVs will place a premium on polymer materials and chemical additives that help EVs withstand extreme heat and electrical conditions. 


Polymer components for EVs are required to shield consumers from the interior battery technology for the electric motor. The high voltage from an all-electric vehicle engine can reach 400 to 600 voltage watts compared to 12 to 48-voltage vehicles currently on the market. Electric cars will experience higher thermal temperature and the possibility of electrical arcing and radio-frequency interference problems. Antioxidant additives play a vital role in manufacturing by providing consumer safety and maintaining regulations and government standards. 


The SI Group offers two main types of antioxidants for use in EV polymer manufacturing: 

1. Primary antioxidants are radical scavengers that remove radicals when formed during the melting process. Primary antioxidants protect against oxidative degradation caused by energy during processing and conversion. 

2. Secondary antioxidants remove organic peroxides that form after primary antioxidants do the job of removing any free radicals.



NAUGARD™ 445 is the ultimate antioxidant technology for the most demanding EV requirements. It retains 5.9% more of its original content, approximately 15 times greater than the following best antioxidant solutions after 60 minutes of exposure. Antioxidants can be lost by physical means, and the volatility level varies between different types of anti-degradant. This antioxidant is unique in the EV industry due to its thermal robustness in high-temperature applications and its ability to increase radical destruction as temperature rises. 

Key Benefits

  • High Molecular weight & low volatility
  • Excellent long-term protection
  • Good Solubility in polyamides with low volatility & migration
  • Synergism with phenols, thioesters, and phosphates


Electric cars require performance polymers for the overall design, aesthetic, and lightweight characteristics. More specifically, filled polypropylene composites provide cost-effectiveness, outstanding mechanical properties, high-performance capabilities, and longer-mile-range vehicles. Replacing traditional car materials allows EVs to go further on a single charge while giving comfort and safety within the car's interior. The SI Group portfolio of POLYBOND® polymer modifiers is comprised of functionalized polyolefin resins bridging incompatible materials.




POLYBOND® 3200 is a highly efficient coupling agent for filled polypropylene systems. Glass-reinforced polypropylene systems are one of the most widely used composites for automotive applications. POLYBOND® 3200 is legendary for improving flexural modulus, tensile strength, and durability for polypropylene composites with long glass fiber reinforced. 

Key Benefits

  • Superior toughness
  • Advanced processing capability
  • Increased thermal stability
  • Improved color yield 


Photo-oxidation degradation is initiated by the UV component of sunlight exposure. Polyolefins absorb UV light due to oxidation products formed during processing or by impurities present in the polymer. Engineering resins and rubber systems absorb UV light due to their intrinsic chemical structure. Automotive polymers are constantly exposed to UV light and varying temperature environments. Therefore, SI Group UV light stabilizers enhance thermal stability and extend the EV life. Photo-oxidation is a mechanism from daily wear and tear that a polymer system may experience.



UV stabilizers protect electric vehicles from degradation that polymer materials face when prolonged exposure to sunlight, UV rays, heat, and reaction with oxygen. Electric cars that experience prolonged exposure to these UV elements without incorporating UV stabilizers can experience polymer degradation such as discoloration or cracks. UV stabilizers protect polymers by absorbing the light and avoiding molecular weight loss, elongation at break, and even impact resistance. Other factors like weathering can break down polymer chains and lead to different degradation mechanisms in the electric vehicle. 


The SI Group offers two main light stabilizing options depending on your polymer-based system. The first route is UV absorbers that retain harmful UV radiation and heat dissipation; this protects the polymer in bulk at its thickest section. The second option is Hindered Amine Light Stabilizers (HALS), which scavenge free radicals, preserve the size and surface, and are activated during light exposure. A well-designed stabilization system will protect the original properties of the EV component resin and improve its longevity from potential polymer degradation.  



LOWILITE™ 77 is an ultra-violet light stabilizer, a highly effective hindered amine additive. This stabilizer additive is suitable for thicker polymeric materials such as exterior bumpers. This grade composes high molecular weight, which allows it to avoid migratory problems. 

Key Benefits

  • Maximizes color yield
  • Improves resistance to acidic environments
  • Can be used alone or in combination with oligomeric HALS
  • Absorbs harmful UV radiation 

Polyurethane foam in the automotive industry is widely used to assist with dampening noise, vibration, and harshness (NVH). The transition from combustion engines to electrified powertrains raises important concerns around NVH and managing this problem. EV motors are quiet compared to combustion engines because traditional engines generate enough noise to dampen road noise making most consumers unaware of any undesirable vehicle characteristics. With EVs, engineers can use polyurethane foam to reduce NVH in the absence of loud engine noise.


Polyurethane foam creates safety, comfort, and multiple performance benefits for EVs. It will become a rapidly growing product used in EV manufacturing for high resilience seating, rigid foam insulation panels, headliners, suspension insulators, and other interior parts of the car. And the SI Group portfolio of polyurethane foam stabilizers protects polyol manufacturers from scorch during processing and degradation in extreme thermal environments. Polyurethane has inherent lightweight characteristics and thermal stability and is capable of multifunctional applications throughout the EV vehicle. Explore the SI Group’s portfolio of antioxidants, stabilizers, and solutions to reduce the overall waste and cost of processing polyurethane foam.




Polymer materials enable EVs to redefine the automotive industry, and the addition of stabilizers is crucial in satisfying consumer and regulatory requirements. The paradigm shift towards renewable and clean energy requires the next generation of polymer technology to defy expectations. The SI Group's portfolio of polymer stabilizers supports polymer components for electric cars by protecting against oxidative degradation, thermal degradation, and photo-oxidation. Talk to one of our specialists today if you want to learn more about which SI Group grade works best for your formulation. 

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