Rapid synthesis of poly(p‐dioxanone)/montmorillonite nanocomposites under microwave irradiation

Abstract

A rapid and ''green'' synthesis of poly(pdioxanone) (PPDO)/montmorillonite (MMT) nanocomposites was carried out smoothly and effectively nder constant microwave powers of 30, 60, 90, and 120 W in a microwave oven at a frequency of 2.45 GHz. The temperature of polymerization was in the range 103-224 C. PPDO, with a viscosity-average molecular weight of 111,000 g/mol and a conversion of 85%, was obtained at 60 W for 10 min, in which the ratio of p-dioxanone to AlEt 3 was 300/1 (mol/mol). The intercalated structure of PPDO/MMT nanocomposites was confirmed by X-ray diffraction and transmission electron microscopy. Thermogravimetry data showed that the thermal stability of the nanocomposites prepared under microwave irradiation was improved with respect to those prepared via conventional heating.

Reactive Coatings in Glass Capillaries: Preparation of Temperature‐ and Light‐Responsive Surfaces and Accurate Determination of Wettability Switching

“…The reverse isomerization into the spiropyran isomer could be induced after 12 h in the dark resulting in a switching to the hydrophobic state. [22][23][24] After UVlight irradiation to yield the merocyanin isomer, the surface was allowed to reisomerize back into the spiroisomer overnight, resulting in Θ equi = 79° and Θ equi = 93°, respectively, which are in very good agreement with the CA values measured before irradiation. This reversibility proves the lightswitchable properties of the obtained surface coatings at 60 °C.…”

“…In the past years, several reports were published on temperature-responsive polymers, containing light-responsive spiropyran moieties. [22][23][24] Spiropyran derivatives are highly interesting candidates for the preparation of light-sensitive polymers because they undergo a chemical photoisomerization induced by irradiation with UV light. Spiropyran isomerizes by a ring-opening reaction upon UV irradiation at typically 365 nm from the spiro-isomer to the colored merocyanine isomer, whereas the reverse isomerization can be triggered by visible light.…”

Meso‐ and Microscopic Motions in Photoresponsive Liquid Crystalline Polymer Films

“…[ 37,38 ] If the lateral polymer density is suffi ciently high, surface brushes are formed, which provide unique molecular orientations and properties. [ 39,40 ] With respect to photoresponsive polymer brushes, there are a number of examples for SI polymerizations of photochromic monomers such as spiropyrans [41][42][43][44] and azobenzenes. [45][46][47] They exhibit fascinating smart responsive functions; however, this review will not touch on them and focuses only to LC brush systems.…”

Simultaneously improving the thermal stability, flame retardancy and mechanical properties of polyethylene by the combination of graphene with carbon black

“…The addition of nanollers into a polymer matrix has been demonstrated to remarkably improve the physical and chemical properties such as mechanical properties and ame retardancy of the polymer matrix. [1][2][3][4] According to nanoller shape, the most commonly used nanollers for polymer nanocomposites can be classied as follows: layered (two-dimension) such as clay [5][6][7][8][9][10] and graphene, 11,12 ber-like (one-dimension) such as carbon nanotubes (CNTs), [13][14][15][16] and spherical (zero-dimension) such as C60 (ref. 17) and carbon black (CB), 18 etc.…”