As an important thermoplastic plastic, thermoplastic polyurethane material is widely used in automobiles, consumer electronics, medical equipment and other fields due to its superior performance. At the same time, silicone rubber occupies an important position in high-end applications due to its unique molecular structure and excellent performance. In recent years, our company's R&D personnel have tried to combine TPU with silicone rubber and developed a new material-TPU-based thermoplastic silicone elastomer.
TPU material is called thermoplastic polyurethane. TPU materialeigenschaften has excellent comprehensive properties such as high strength, high toughness, wear resistance, oil resistance, etc., and has good processing performance. It is widely used in defense, medical, food and other industries.
The molecular structure of thermoplastic polyurethane material is composed of rigid blocks obtained by the reaction of diphenylmethane diisocyanate (MDI) or toluene diisocyanate (TDI) and chain extenders, and flexible segments obtained by the reaction of diisocyanate molecules such as diphenylmethane diisocyanate (MDI) or toluene diisocyanate (TDI) and macromolecular polyols.
TPU material not only has excellent performance, but also has the characteristics of being degradable (3-5 years) and recyclable. It can be degraded in the natural environment, becoming a biodegradable substance, and completely decomposed in a short time.
TPU material is an important class of thermoplastic materials and has been widely used in many fields. It is still necessary to prepare a TPU material that maintains its original physical and chemical properties when continuously heated to a certain temperature such as (-120-150℃). Blending has been recognized as a simple and flexible method to improve the performance of polymers and has been applied in the industrial field.
Silicone rubber has a unique molecular structure, with silicon and oxygen atoms alternately connected to form a huge skeleton. It contains both organic and inorganic components. The special structure makes silicone rubber have many high performances, such as biocompatibility, high air permeability, high flexibility, good dielectric properties and chemical stability, wide temperature range (-100-250℃), good thermal stability and oxidation stability, low glass transition temperature, and resistance to ultraviolet radiation. In the past decade, silicone rubber has been widely used in electronic and building materials and biomedical materials.
However, due to the high toughness of silicone rubber and the low cohesive energy between the main chain molecules, the mechanical properties of silicone rubber are poor, such as low tensile strength, intolerance to hydrocarbon oils and solvents, and high prices. Therefore, the application of silicone rubber in some fields is limited and challenged.
Researchers combine TPU materials with silicone materials, which can be blended through dynamic vulcanization to obtain better performance. This combination can take advantage of the high strength and toughness of TPU materials and the high temperature resistance and chemical resistance of silicone to form a new type of composite material. This material combines the wear resistance and oil resistance of TPU with the high temperature resistance and chemical resistance of silicone, which broadens the application field.
TPU-based thermoplastic silicone elastomer is a block copolymer, which is copolymerized by hard (rigid) segments and soft (flexible) segments. This structure determines that this type of polymer has a microphase separation morphology and two glass transition temperatures. The flexible part shows the role of elastomer, and the rigid part shows the role of filler. They are like highly dispersed reinforcing "filler" particles, uniformly dispersed in continuous polysiloxane chains, and play a physical cross-linking role. This cross-linking effect is thermally reversible. Blended thermoplastic silicone elastomer obtained by dynamic vulcanization blending technology.
| Performance advantages of TPU-based thermoplastic silicone elastomer-TPSiV | ||||
| Clean chemical reaction | Does not contain solvent oil | The surface is not easy to absorb dust | Excellent adhesion to many thermoplastic engineering plastics. | After high temperature aging at 150℃, it can still maintain high mechanical strength |
| No by-products | Does not contain plasticizer | Oil-resistant | Can be used for co-extrusion and two-color injection molding | Can be used for secondary processing such as silk screen printing, pad printing, spray painting, etc. |
| No odor | \ | Chemical-resistant | \ | \ |
| No volatiles | \ | Not easy to be polluted | \ | \ |
1. Hydrolytic stability
The organic segments and siloxane segments in the block copolymer are connected by Si-0-C bonds. This bond is unstable in "non-block" copolymers, but in this alternating segment copolymer, it shows excellent hydrolytic stability. Solutions of these block copolymers also show good hydrolytic stability, and their molecular weight has little change even after reflux in aqueous tetrahydrofuran solution for 3 days.
2. Thermal stability and thermal oxidation stability
In general, thermoplastic silicone elastomers have good thermal stability and thermal oxidation stability. They have a wide application temperature range (-120-250°C), which is given by the low-temperature properties of polysiloxane and the high-temperature properties of the organic hard part.
3. Mechanical properties
It has the flexibility and high strength of silicone; compared with general thermoplastic elastomers TPE, TPV, TPU materials, etc., silicone elastomer TPSiV has better tensile and tear strength, better resistance, better compression elastic deformation at high temperature, better UV resistance and heat resistance.
Thermoplastic silicone elastomers (TPSiV) have a wide range of applications, thanks to their unique physical and chemical properties, such as excellent high and low temperature resistance, good wear resistance, hydrolysis resistance and chemical resistance, as well as environmentally friendly and recyclable characteristics.
The following are some of the main application areas:
Consumer electronics: TPSiV is widely used in consumer electronics products, such as housings and protective covers of mobile phones, computers and other devices, due to its excellent high temperature resistance, low stretch and compression, and good wear resistance.
Automotive industry: TPSiV is used in the automotive industry to manufacture various components, including seals, protective parts, suspension systems, seat support pads, etc., thanks to its good oil resistance and weather resistance.
Medical devices: TPSiV's biocompatibility and disinfection resistance make it widely used in the field of medical devices, such as medical earplugs, infusion sets, gloves, etc.
Wearable devices: TPSiV is used in the field of wearable devices due to its skin-friendly, antibacterial, UV-resistant, heat-resistant and other properties, providing a more comfortable user experience.
Wires and cables: TPSiV has excellent flame retardancy, oil resistance and weather resistance, and can be used to produce various high-demand wires and cables.
Angreen solves the problem of the performance of SiR/TPU and analyzes the relationship between the microscopic phase and performance of the material through simple, efficient and low-cost technical methods.
1. Study the changes in the mechanical properties, elasticity and rheological processing properties of SiR/TPU with the change of the blending ratio, and determine the blending ratio with the best performance.
2. Use AFM to observe the microscopic phase structure, analyze and study the changes in the phase structure of SiR/TPU with the change of TPU blending dosage, such as the dispersion and size changes of dispersed particles, and connect the mechanical and elastic properties of the material to conduct structure-performance relationship analysis.
1. By post-processing SiR/TPU with different thermoplastic polyurethanes, SiR/TPU blended materials were successfully made, which successfully improved the tensile strength, elongation at break and hardness of the material and improved the mechanical properties of the material.
2. The study revealed the relationship between the changes in the microscopic phase structure of different SiR/TPU with the change of the blending ratio and the mechanical properties and processing rheological properties.
The combination of TPU material and silicone not only forms a new type of high-performance material, but also has the characteristics of environmental protection and sustainability.
