Solution mixing polycarbonate

Figure 2.2. Schematic of synthesis of CNT polycarbonate nanocomposites by solution mixing approach. Reproduced from reference 19 with permission from American Chemical Society.

Modified silicon-containing polycarbonates have been prepared in solution and their transition temperatures assessed. Block copolymers of bisphenol-A-polycarbonate-bisphenol-A-polysulphone and acrylates and methacrylates grafted onto polycarbonate film have also been prepared and evaluated, as have mixed polycarbonate systems based on 2,2 -bis(4-hydroxyphenyl)propane, 2,2 -bis(4-hydroxy-3,5-dibromophenyI)propaneandtetrabromophenophthalein. Molecular relaxations in aliphatic polycarbonates have been studied by the method of thermally-stimulated currents and the thermal ageing of polycarbonates based on polycyclic diphenols has been assessed by studies of mechanical properties. 

Melt processing has been successfully applied for the preparation of different polymer-CNT composites such as PP/CNT [211-213], PE/CNT [212-216], polycarbonate (PC)/CNT [217-219], PMMA/CNT [220-223], poly-oxymethylene/CNT [224], polyimide/CNT [225], PA6/CNT [226,227], and so on. The shear forces from the mix-ers/extruders should help break nanoparticle aggregates or prevent their formation. Unfortunately, the dispersion of CNTs in a polymer matrix is quite poor compared to the dispersion that may be achieved through solution mixing. In addition, the CNTs must be lower due to the high viscosities of the composites at higher loading of CNTs. 

The lipid and plasmid solutions are preheated to 37°G before mixing together. After mixing these solutions for 10 min, ethanol is evaporated under the reduced pressure. The samples are filtered through 0.2 pm polycarbonate filters and stored at 4°C until use. 

A polycarbonate was mixed with 2 to 15 wt% LC silicone and dissolved in methylene chloride. The solutions were cast and dried to produce films. After that, the films were stretched at about 180 °C and subsequently cooled down to room temperature. The resulting films have a thickness of about 100 pm and a low haze of less than 3 %. Their optical retardation as a function of temperature was measured by the Senarmont method using a laser beam and a hot stage. Typical retardation values of the TCR films produced with the LC silicone of Rg. 1 are 400 nm to 600 nm at 30 °C and 200 nm to 400 nm at 80 °C. 

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