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The synthesis and properties of amorphous poly-(tricyclodecanedimethylene-co-isosorbide terephthalate) (PTIT) with the isosorbide (IS) content ranging from 0 to 68 mol % relative to the total diol amount were investigated. Surprisingly, it was found that isosorbide enhanced the polycondensation kinetics and acted as a temporary chain linker. Polymerization kinetics improvement maximum was observed when the isosorbide content was around 9 mol %. It was also found that higher molar masses were achieved when the isosorbide molar content was increased (number-average molar mass, M n , around 16,000 g mol −1 ). The glass transition temperature linearly increased of 0.7 °C per mol% of isosorbide for each molar percent of isosorbide included in the polyester. The T g values of the polyesters could be adjusted between 115 and 163 °C, depending on the isosorbide content. Their mechanical properties were investigated, and ductile properties were achieved up to 57 mol % of isosorbide. These properties are coupled with a very high heat deflection temperature (HDT).

The injection molding of a microfeatured component, a diffractive optical element, was studied. The component has a wave‐like pattern on the surface, with amplitude 0.5 μm and wavelength 3 μm. Two different polymers were used: a polymethylmethacrylate and an ethylene‐norbornene copolymer (cyclic olefin copolymer). The topography was investigated using white light interferometry (WLI), atomic force microscopy (AFM), and scanning electron microscopy (SEM). A new WLI‐based technique is proposed for rapid quantification of the replication of periodic surface patterns. This technique gives almost the same information regarding the degree of replication as AFM but can be performed much faster. Quantitative data on the degree of replication as function of processing conditions are presented. At optimal conditions, almost perfect replication is obtained using both materials. At suboptimal conditions, it is observed that the degree of replication increases with increasing injection velocity and increasing mold temperature, with similar characteristics for both materials. The difference in replication quality between the two materials seems to be related to the different temperature dependencies of the viscosities. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers

The injection molding of an optical grating was studied using two different polycarbonates. The grating had period 10 μm and peak-to-valley distance ∼1 μm. Parts were molded using different holding pressures and mold temperatures. After production, the parts were annealed at 100°C. The replication was investigated using white light interferometry (WLI) before and after annealing. WLI was performed using high definition vertical-scanning interferometry (HDVSI) to resolve the details of the molded gratings with a noise level below 2 nm.It was observed that increasing the holding pressure could have either a positive or a negative effect on the replication. When the microfeatures were not fully filled, an increased holding pressure improved the definition of the features. However, for both polymers, it was observed that the replication as a function of holding pressure started to drop when the holding pressure was increased above an optimal value. This could be due to an elastic recoil occurring after releasing the holding pressure.The peak-to-valley distance of the grating was reduced after annealing. This effect was larger for parts molded using a low mold temperature. This is probably due to a higher cooling rate giving higher internal stresses, which will relax during annealing.