Effects of the Processing Parameters on the Shear Viscosity of Cyclic Olefin Copolymer Plasticized by Ultrasonic Vibration Energy

Abstract

Shear viscosity of the cyclic olefin copolymer (COC) plasticized by ultrasonic vibration energy is characterized by high pressure capillary rheometer. Two different plasticization modes were adopted to prepare the samples with an in-house developed prototype machine. Single-factor experiments were conducted to investigate the effects of ultrasonic energy on the shear viscosity. The influences of the processing parameters and the plasticization modes were analyzed and compared. The results showed that the shear viscosity of COC was reduced under various parameter combinations, and demonstrated a significant difference in the lower shear rate range in comparison with the control samples; the results of gel permeation chromatography (GPC) showed that the COC’s number average molecular weight ( M ¯ n ) was decreased and the polymer dispersity index (PDI) was increased due to the plasticization by ultrasonic vibration energy. This could be further account for the decrease of the shear viscosity of COC. Moreover, the predominant ultrasonic parameter changed in different modes of plasticization according to the statistical analysis based on the Statistical Product and Service Solutions (SPSS) software.

Ultrasonic nodal point, a new configuration for ultrasonic moulding technology

“…Even if the technology has been usefully proven to process a wide range of materials, some works reported low filling repeatability [21], inhomogeneous thermal conditions in the polymer melt [12], unstable mechanical properties [23] and heterogeneous plasticization [24]. In fact, the authors of the present paper consider that the lack of stability is the main drawback for this technology nowadays [9].…”

Manufacturing PLA/PCL Blends by Ultrasonic Molding Technology

“…Comparing the PCL and PLA material before and after being processed, USM increased both the and the PI. Thus, the ultrasound vibration energy induced chemical reactions, leading to crosslinking between the molecular chains of the material [ 39 ] or molecular segregation caused by the integration of lower-molecular-weight chains that melted first and incorporated into the small regions acting as joints between pellets [ 34 ]. When single polymers were processed, the decreased from the beginning to the end of the specimen (13% in PLA and 3% in PCL), whereas the PI increased (28% in PLA and 12% in PCL) ( Figure 7 ), which agrees with the trend found in the literature [ 47 ].…”

“…When single polymers were processed, the decreased from the beginning to the end of the specimen (13% in PLA and 3% in PCL), whereas the PI increased (28% in PLA and 12% in PCL) ( Figure 7 ), which agrees with the trend found in the literature [ 47 ]. This means that molecular chain scissions occurred during the cavity filling, probably because of the movement produced by the ultrasonic vibration [ 39 ]. However, when the blends are analyzed, the trend is the other way around, so that both and PI increased from the beginning to the end ( Figure 7 ), this increment being influenced by the PCL portion into the blend.…”

“…USM technology applied to polymers is currently under investigation with different approaches. The first approach focuses on analyzing the processability of homopolymers, such as polypropylene (PP) [ 30 ], polylactic acid (PLA) [ 34 , 35 ], polyamides (PAs) [ 36 ], polystyrene (PS) [ 27 ], polyphenylsulfone (PPSU) [ 37 ], polyether ether ketone (PEEK) [ 38 ] and cyclic olefin copolymer (COC) [ 39 ], among others. In the second approach, the technology is used to process components of polymeric blends, composites or nanocomposites.…”

Establishment of an in vitro thrombogenicity test system with cyclic olefin copolymer substrate for endothelial layer formation

“…[ 14 ] GPC analysis revealed a number average molar mass M n = 14.4 ± 0.4 kg mol −1 of COC and a polydispersity index M w / M n of 1.98. Compared with the other commercial cyclic olefin copolymers, [ 15 ] it has to be pointed out that the values given here were determined from universally calibrated GPC, while the literature values were determined by standard calibration, [ 15 ] which may also be the reason for the differences.…”