Novel crosslinked nonlinear optical materials based on cellulose diacetate

Abstract

Preparation of second-order nonlinear optical (NLO) materials based on cellulose diacetate and melamine derivatives was attempted. The NLO chromophore DR19 was incorporated into the crosslinking network resulting from the reaction of cellulose diacetate with trimethylolmelamine or hexamethylolmelamine. The poled and cured NLO materials exhibited electrooptic coefficient (r 13 ) values of 1.11 or 1.03 pm/V, respectively, at a laser wavelength of 1550 nm, a modulation frequency of 12.7 kHz. The r 13 values decreased to 80 or 81.5% of the initial values after 4 days.The laser transmission loss was 0.50 or 0.44 db. The crosslinking materials showed better temporal stability than that of host/guest type materials, and 73% of the initial r 13 value remained after keeping the NLO film at 100°C for 15 h. No evident weight loss was found below 250°C.

Facile carbohydrate-mimetic modifications of poly(ethylene imine) carriers for gene delivery applications

“…Moreover, as already established while reacting diamino-functionalized PEG and pF in organic solvents, 64,65 transient species are kinetically-quenched to form gels, owing to the polymeric nature of the amine. Both these observations precluded accurate identification of the crosslinks with PEI in aqueous conditions, which was most likely a mixture of aminals and hemiaminal ethers as previously reported for melamine/formaldehyde resins 66,67 and possibly a small quantity of hexahydrotriazine crosslinks. 63,64 NMR experiments on the reaction of LPEI with >0.5 equiv.…”

Flame retardancy of polyamide 66 nanocomposites with thermally stable organoclay

“…In the present study, a thermally stable imidazolium organoclay was synthesized and melt‐compounded with PA 66 using a twin‐screw extruder. To improve the flame retardancy of the PA 66 nanocomposites, monomethylol melamine (MMM) was synthesized20–22 and used to coat the thermally stable organoclay before melt‐compounded with PA 66. For comparison purpose, melamine was additionally incorporated with the PA 66/orgnaoclay nanocomposites during melt‐compounding as an environmentally friendly flame retardant.…”