Optical gradient materials produced via low-temperature isothermal frontal polymerization

Abstract

Using a newly developed low-temperature frontal polymerization technique, poly(methyl methacrylate) (PMMA) matrices were prepared with nonuniform distributions of organic nonlinear optical dyes, with potential use as optical limiters. This technique affords lower temperature conditions than have been used before. A PMMA tube was filled with a dye, the initiator tert-butyl peroxide, and methyl methacrylate (MMA). Curing at 4°C resulted in a radial gradient of dye. An axial dye gradient was observed when MMA was overlaid and polymerization effected from a dye-doped PMMA seed using tricaprylmethyl ammonium persulfate as the initiator. In both cases, polymerization reactions were observed as a result of isothermal frontal polymerization with the subsequent formation of a nonlinear concentration distribution of the optical dye dopants. Low temperatures are desirable to eliminate thermal and photothermal degradation of temperature-sensitive dyes during the polymerization. The preparation of long polymer rods with organic dye gradients on the scale of several centimeters can also be realized with the use of low-temperature polymerization and the gradients controlled by the concentration of initiator.

Influence of a Melt Flow on Generation of Functionally Graded Structure in Bulk Polymeric Materials under Uniaxial Thermal Gradient

“…[8][9][10][11][12][13] Polymeric bulk FGMs have potentials for various applications, such as bone substitution materials, [14][15][16][17] joint replacements, [7,18] and optical limiters. [19,20] To fabricate the bulk FGMs by a simple procedure, we have firstly applied a Bridgman method, which is an attractive technique using directional solidification, for the preparation of bulk single crystals and purification of metals, [21,22] inorganic, [23,24] and low molecular organic crystals [25,26] to polymer blends and succeeded to fabricate compositionally graded bulk materials. [27] In the poly(e-caprolactone) (PCL)/poly(ethylene oxide) (PEO) blend system, which is utilized as porous PCL scaffolds after selective dissolution of PEO with water, [28,29] the content of PEO was decreased with respect to the solidification direction.…”

Isothermal Frontal Polymerization

“…In addition to using IFP systems with dopants to produce a specified GRIN product, researchers determined that IFP could exist outside traditional cure temperatures. Masere et al produced IFP GRINs below room temperatures using the initiator tricaprylmethylammonium persulfate [51].…”

Investigation of redox initiators for free radical frontal polymerization

“…They investigated the macrokinetics and dynamics of FP 12, 13. Considering FP has advantages over traditional methods of polymerization in terms of reduced energy costs, reduced waste production and unique morphology, a great deal of work on this versatile and facile methodology for synthesizing various polymers has been performed 14–31…”