Ecofriendly Autoxidation of Castor Oil/Ricinoleic Acid. Multifunctional Macroperoxide Initiators for Multi Block/Graft Copolymers

Abstract

Ecofriendly autoxidation is a reaction of air oxygen with unsaturated organic molecules at room temperature. Castor oil and ricinoleic acid were ecofriendly autoxidized for 5 months to obtain castor oil macroperoxide with a Mn of 1935 g mol−1 (Pcast5m) and the ricinoleic acid macroperoxide initiator (Prici5m) with a Mn of 1169 g mol−1. Peroxide groups thermally initiated the free radical polymerization of methyl methacrylate (MMA), n‐butyl methacrylate (nBMA), and styrene (S). Peroxide formation in the oxidized castor oil and ricinoleic acid was confirmed using iodometric analysis, elemental analysis, and differential scanning calorimetry technique. Peroxide decomposition in both macroperoxide initiators was observed at 166 °C for Prici5m and 170 °C for Pcast5m. Hydroxyl groups of Pcast5m were reacted with methacryloyl chloride to obtain methacrylated castor oil macroperoxide (PcastMA). The polymerization rates of the obtained macroinitiators were compared. The polymerization rate order is Pcast5m > Prici5m > PcastMA. Polymerization of styrene by PcastMA resulted in an increase in molar masses and an increase in the polymerization time while those of the styrene polymerization by Pcast5m and Prici5m remained constant. Carboxylic acid groups were reacted with amine‐terminated polyethylene glycol (PEG), polydimethyl siloxane (PDMS), and polytetrahydrofuran (PTHF) while the hydroxyl functionality initiated the ring‐opening polymerization of ε‐caprolactone (CL). Prici‐PEG‐PMMA, Prici‐PS‐PDMS, Prici‐PS‐PTHF, Pcast‐PS‐PCL, Pcast‐PCL‐PMMA, and Pcast‐PS‐PnBMA multiblock copolymers were prepared and characterized using spectrometric, thermal, and stress–strain measurement techniques.

Prevention of urinary infection through the incorporation of silver–ricinoleic acid–polystyrene nanoparticles on the catheter surface

“…The characteristic macroperoxide (-CH-OH), -CH-Osignal and double bonds of PRici were observed at 3.6 ppm; 5.2 ppm and 5.4-5.6 ppm, respectively. The characteristic peak of PS was seen at 6.5-7.0 ppm 35 (Figure 2(a)).…”

“…Here, peroxide content of PRici was almost the same with oleic acid macroperoxide initiator. 35 The thermal analysis of the copolymers was carried out under nitrogen atmosphere by TA Instruments SDT 650 Simultane DSC/TGA Thermal Analysis System. DSC measures the temperature and heat flow in relation to the thermal transfer of the polymer sample obtained.…”

Macro peroxide initiators based on autoxidized unsaturated plant oils: Block/graft copolymer conjugates for nanotechnology and biomedical applications

“…Three double bonds containing linolenic acid oxidize faster than two double bonds containing linoleic acid (18:2) and one double bond containing oleic acid and ricinoleic acid. Two weeks' autoxidation is enough to obtain high viscous linseed oil with high content linolenic acid (three double bonds; 18:3; Hazer & Ashby, 2023) while four months are needed to obtain oligomerized oleic acid (18:1; Hazer et al, 2017; Hazer et al, 2019) and ricinoleic acid with one double bond (18:1; Hazer & Eren, 2019).…”

“…A mixture of castor oil macro peroxide, styrene monomer, and ε‐caprolactone undergo thermally one‐pot polymerization leading to PCL‐PS‐castor oil multi‐graft copolymer (Hazer & Eren, 2019). Peroxide formation can be observed by differential scanning calorimeter (DSC) analysis showing characteristic exothermic decomposition peak emerging between 90 and 150°C (Litwinienko & Kasprzycka‐Guttman, 2000; Murthy et al, 1994).…”

“…Ricinoleic acid can be eco‐friendly autoxidized in 5 months under atmospheric conditions to obtain Prici containing five functionalities such as hydroxyl, carboxylic acid, peroxide, plasticizer, and macrostructure. Free radical polymerization of styrene, ring‐opening polymerization of ε‐CL and condensation polymerization of amine‐terminated PEG can be carried out in one pot to produce a multiblock graft copolymer (Hazer & Eren, 2019).…”