Polycarbonate Rod (PC Rod) is made from polycarbonate (PC) resin through precision extrusion technology. Its molecular basis is derived from the linear polycarbonate macromolecular chain generated by ester exchange reaction between 2,2 '- bis (4-hydroxyphenyl) propane (bisphenol A) and diphenyl carbonate (DPC). The benzene ring structure (- C ₆ H ₄ -) contained in the main chain of PC molecules alternates with the carbonate group (- O-C (=O) - O -), and through the synergistic effect of intramolecular hydrogen bonding and van der Waals forces, a highly rigid main chain architecture is constructed. The molecular weight distribution of typical PC resin is in the range of 20000~40000 g/mol, and the physical crosslinking effect is achieved between molecular chains through hydrogen bonding (forming a three-dimensional hydrogen bonding network with a density of about 0.35 nm ³). This unique semi crystalline amorphous mixed structure (crystallinity usually less than 10%) endows PC rods with excellent mechanical and optical properties.
From a microscopic perspective, the molecular chain arrangement of PC rods exhibits a "combination of rigidity and flexibility" feature - the benzene ring structure provides rigid support for the molecular chain, while the flexible ether bonds of carbonate groups endow the chain segments with moderate mobility. Dynamic mechanical analysis (DMA) confirmed that its glass transition temperature (Tg) is as high as 145-150 ℃, and its storage modulus (E ') exhibits a plateau distribution above Tg (1.2-1.8 GPa), which is 300% higher than polystyrene (PS) and demonstrates excellent thermal mechanical stability. Fourier transform infrared spectroscopy (FTIR) shows that the introduction of trace additives (such as anti UV stabilizers) during the processing can fine tune the intermolecular forces, but the main chain structure remains intact and does not affect the core performance.
Performance
Mechanical properties
Impact resistance: The notch impact strength is ≥ 60 kJ/m ² (23 ℃), much higher than ABS and PMMA, and close to some metal alloys.
Creep resistance: Low deformation rate under continuous load (<1% @ 70 ℃/20MPa/1000h).
Bending strength: 90-110 MPa, elastic modulus 2.3-2.5 GPa.
Thermal performance
Hot deformation temperature (HDT): 130-140 ℃ (1.82MPa load), short-term temperature resistance can reach 120 ℃.
Linear expansion coefficient: 6-7 × 10 ⁻⁵/℃, attention should be paid to the size stability design when the temperature difference is large.
Optical and electrical properties
Transmittance: Transparent grade PC can reach 88-92% (3mm thickness), available in frosted or dyed models.
Dielectric strength: 15-20 kV/mm, volume resistivity>10 ¹⁶Ω· cm.
Chemical stability
Resistant to weak acids, weak bases, and alcohols, but susceptible to strong bases, ketones, and chlorinated hydrocarbons.
UV resistant models can achieve outdoor weather resistance for more than 10 years by adding coatings or modifications.
In the field of optical engineering, PC rods with a birefringence coefficient less than 1 × 10 ⁻⁵ (such as Zeonex) ® The series is used for high-precision optical components such as laser collimators and fiber adapters. A certain laser cutting equipment manufacturer uses a Φ 20mm × 1000mm PC rod to make an optical path guide sleeve. The laser transmission loss is only 0.2%, and under long-term stable operating conditions, the spot deviation is less than λ/10 (λ=650nm). In the field of AR/VR, free-form surface PC lenses achieve non spherical accuracy<0.005mm, thickness tolerance ± 0.02mm, refractive index nd=1.586 (400nm), and Abbe number Vd=30 through injection compression molding, and have been successfully applied to Meta Quest Pro display modules.
In precision instruments and meters, PC rods are processed into miniature bearings (inner diameter Φ 3mm × outer diameter Φ 10mm × length 15mm) instead of brass products, reducing the friction coefficient from 0.12 to 0.08 (ISO 14635 standard) and extending the service life by 5 times. In the aerospace field, radiation resistant PC rods (with added cerium oxide stabilizer) have undergone space environment simulation testing (10 ⁻⁶ Pa vacuum, 1 MeV electron irradiation), with a performance degradation of less than 5%. They are used for satellite support structural components and achieve 10-year maintenance free in orbit. In terms of medical devices, medical grade PC rods (ISO 10993 certified) have been sterilized by gamma rays, with a dissolved matter content of less than 1 ppm (TOC detection) and a surface roughness Ra of 0.2 μ m. They are used for insulin pump housings and blood dialysis equipment components.
In the field of industrial manufacturing, wear-resistant PC rods (with PTFE micro powder added) are used for food packaging machinery guide rails, with a PV value exceeding 2.5 MPa · m/s and a wear rate of<1 × 10 ⁻⁷ mm ³/(N · m), which is 80% lower than stainless steel guide rails. The front headlight reflector cup of the car adopts PC rod secondary molding technology, and its temperature impact resistance has passed the cold and hot cycle test of -40 ℃~85 ℃ (500 times without cracking), and the brightness has been increased by 15% (the luminous flux has increased from 12000lm to 13800lm). In building curtain walls, double-sided UV coated PC rods (with a film thickness of 50nm) are used as shading components, reducing the solar heat gain coefficient (SHGC) from 0.75 to 0.38 while maintaining a visible light transmittance of>65%, helping green buildings reduce energy consumption by 18%.
