Soybean oil‐based shape‐memory polyurethanes: Synthesis and characterization

Shape‐memory polymers (SMPs) have wide range of applications due to their ability to sense environmental stimuli and reshape from a temporary shape to a permanent shape. Plant oil‐based polymeric materials are highly concerned in recent years in consideration of petroleum depletion and environmental pollution. However, plant oil‐based polymers are rarely investigated regarding their shape‐memory characteristics though bio‐based SMPs are highly desired nowadays. In this study, a series of soybean oil‐based shape‐memory polyurethanes (SSMPUs) are prepared through a mild chemo‐enzymatic synthetic route, and their properties are fully characterized with tensile testing, DSC, dynamic mechanical analysis (DMA), and shape‐memory testing. Results show that SSMPUs are soft rubbers with tensile strength in the range of 1.9–2.2 MPa and glass transition temperature in the range of 2–5°C, and possess good shape recoveries at RT when stretching ratio is 10, 20, and 30%, respectively. This work would promote the development of high‐value‐added plant oil‐based shape‐memory polyurethanes. Practical applications: Using annual renewable plant oil as feedstock, the synthesized SSMPUs show good shape recovery properties, which will make them applicable as potential alternatives to petroleum‐based shape‐memory materials. The simple and mild preparation process also contributes to the further exploration of plant oil to value‐added functional materials.     

Preparation of open‐cell foams from polymer blends by supercritical CO2 and their efficient oil‐absorbing performance

This letter reports on the hydrophobicity and oleophilicity of open‐cell foams from polymer blends prepared by supercritical CO₂. A typical bulk density of the foam is measured to be 0.05 g/cm³. The contact angle of the foam with water is determined to be 139.2°. The foam can selectively absorb the diesel from water with the uptake capacity of 17.0 g/g. The foams are technologically promising for application of oil spill cleanup. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4182–4185, 2016     

Fast continuous‐discrete DAF‐filters

This article introduces a new method for nonlinear continuous‐discrete filtering. It is shown that the Fokker–Planck‐equation can be solved numerically by using distributed approximating functionals (DAFs). The approximation is very accurate and resolves the time interval between observations in one calculation step. Additionally, the operator matrix has to be evaluated only once and not necessarily online. Therefore, the method is very efficient.     

Plant oil‐based biofoam composites with balanced performance

BACKGROUND: Biofoam composites were prepared using short sisal fibers as reinforcement and acrylated epoxidized soybean oil as matrix, aiming at replacing traditional unsaturated polyester foams in structural applications. The compressive properties of the composites were examined as a function of fiber loading, fiber length and foam density. RESULTS: The foam composite with 10 phr (parts per hundred of base resin by weight) sisal fiber possessed properties similar to those of commercial unsaturated polyester foams. A study of the failure mechanism revealed that debonding between fiber and matrix was a key issue responsible for catastrophic damage of the composites. According to this finding, surface pre‐treatment of the sisal using an alkali or silane coupling agent was carried out. This brought about positive effects on interfacial interaction and compressive strength of the composites, as desired. Also, soil burial tests proved that the foam composites could be biodegraded, and the incorporated sisal fibers accelerated the biodegradation of the composites. CONCLUSION: This work shows the feasibility of making rigid biofoams from natural resources, which could be potential candidates for structural foams. Copyright © 2009 Society of Chemical Industry     

Enzymatic oil‐degumming by a novel microbial phospholipase

Phospholipase A‐mediated oil‐degumming is a well‐established process step (Enzy‐Max^®) in physical refining of vegetable oils (rape seed, soy bean, sunflower seed). A screening programme for microbial phospholipases of type A has been carried out. The target has been to develop a stable and robust phospholipase with optimal oil‐degumming performance in the pH‐range 4—5 and in the temperature range 30— 70 °C. One phospholipase of type A1 from Fusarium oxysporum, given the trade name Lecitase^® Novo, has been studied in detail. Some of the characteristics of this novel microbial phospholipase in the oil‐degumming application are: pH optimum ∼5, temperature optimum 40—45 °C. In laboratory tests the new phospholipase Lecitase^® Novo has proven to be superior to porcine pancreatic Lecitase^® 10L and other phospholipases with respect to oil‐degumming performance, and it has proven to be suited for degumming of different oil qualities ranging from water‐degummed to crude oil. A further advantage is that the new phospholipase acts at very low water content, which will make the problematic sludge recycling in the EnzyMax^® process superfluous. As demonstrated by an HPLC study, phospholipase‐mediated degumming is a unique process quite distinct from the well‐known acid degumming variations, since the phospholipids (both hydratable and non‐hydratable) present in the oil are hydrolysed to the corresponding lyso‐phospholipids, which migrate to the aqueous phase under the conditions employed. Lecitase^® Novo was introduced successfully for degumming of rapeseed oil at Cereol (Mannheim, Germany) mid 2000.     

High oil‐absorptive composites based on 4‐tert‐butylstyrene‐EPDM‐divinylbenzene graft polymer

4‐tert‐Butylstyrene‐EPDM‐divinylbenzene graft polymer (PBED) was prepared by graft crosslinking polymerization in toluene using BPO as an initiator. Gel and sol of PBED were isolated by extraction with tetrahydrofuran (THF). Sol PBED can be reused as oil absorbent through cross‐linking by ultraviolet irradiation. After swelling in oil, crosslinked polymers have poor gel strength to be taken out of oil wholly at high absorbency, although they possess strong mechanical strength in their dry states. As known, composite technique is one of the useful methods for material reinforcement. Fibres, sponges and non‐woven fabrics were used as reinforcers or supporters in this work. Oil absorbency was measured by method ASTM (F726‐81) and swelling kinetics of the composite was evaluated by an experimental equation. The gel strength parameter S, the relaxation exponent n, and the fractal dimension d_f of polymer and some composites in pseudo‐critical gel state were determined from oscillatory shear measurements by a dynamic rheometer. Mechanical properties and the morphologies of some composites were measured with a tensile tester and scanning electron microscopy, respectively. © 2001 Society of Chemical Industry     

Antibacterial N‐halamine coating on cotton fabric fabricated using mist polymerization

3‐Methylallyloxy‐5,5‐dimethylhydantoin (MH), an methacrylate monomer containing N‐halamine moiety, was synthesized by 5,5‐dimethylhydantoin (DMH) and methacryloyl chloride. Antimicrobial coating of poly[1‐methyl‐1‐(4,4‐dimethyl‐2,5‐dioxoimidazolidin‐carbonyl)ethylene] (PMH) was prepared on cotton fabrics via “mist polymerization” using MH as monomer. The coating gave the cotton fabric with efficient antibacterial function with remarkable durability. In the antibacterial tests, the bacteriostatic reduction rate is greater than 99.78%, and can be maintained over 99.00% even after 30 washing cycles. Compared with other antimicrobial technologies, mist polymerization offers advantages such as achieving antimicrobial function by small consumption of monomer, forming coatings on single‐side of the fabrics, and minimizing the damages on the original properties of cotton during the finishing process. It can be applied in a wide variety of textile products such as sportswear, underwear, socks, and medical textiles. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44897.     

Swelling kinetics of linseed oil‐based nanocomposites

The solvent‐resistance properties of the montmorillonite‐filled conjugated linseed oil‐based nanocomposites are studied in tetrahydrofuran through equilibrium swelling method at different temperatures. The values of “n” in solvent transport equation are found to be below “0.5,” showing the non‐Fickian diffusion in the polymer. The dependence of the diffusion coefficient on the composition, percentage of clay, and temperature has been studied for nanocomposite samples. The diffusion coefficient increases with an increase in the clay contents and temperature. The crosslink density of the nanocomposites ranges from 101.07 to 237.46 × 10⁶ mol/cm³. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Three‐dimensionally printed bioinspired superhydrophobic PLA membrane for oil‐water separation

A novel lotus‐leaf‐inspired superhydrophobic poly(lactic acid) (PLA) porous membrane was fabricated for oil‐water separation based on fused deposition modeling three‐dimensional printing and subsequent chemical etching and the decoration of polystyrene nanospheres. A superhydrophobic PLA fractal surface with a water contact angle of 151.7° and low water adhesion force of 21.8 μN was achieved. The membrane pore size could be easily adjusted from 40 to 600 μm via a computer‐aided design program to optimize separation performance. The maximal oil‐water separation efficiency of 99.4% was achieved with a pore size of 250 μm, which also exhibited a high flux of 60 kL m^?2 h^?1. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3700–3708, 2018     

Polymerizable oil‐in‐oil emulsions: poly(vinyl pyrrolidone) dispersions in reactive PDMS medium

The system N‐vinyl‐2‐pyrrolidone (VP)/polydimethylsiloxane diglycidylether (PDMS‐DGE) is a typical example of an oil‐in‐oil emulsion formed by two non‐miscible liquids, where both phases are polymerizable in a ‘one‐pot’ procedure by two distinct reaction mechanisms. These oil‐in‐oil emulsions were characterized by their stability and by the particle size of the dispersed VP phase. Non‐aqueous dispersions (NADs) are obtained in a first step by free radical polymerization of the dispersed VP phase. The reaction kinetics, studied as a function of the initiator type and concentration, show that the polymerization rate is mainly influenced by the partition coefficient of the initiator between both phases. The NAD particle size could be tailored from a micrometer to a nanometer range by in situ formation of PVP‐PDMS graft copolymer. Hydrophilic–hydrophobic two‐phase materials can be obtained by polycondensation, in the presence of polyamines, of the epoxy‐functionalized PDMS continuous NAD phase. Copyright © 2007 Society of Chemical Industry     

Synthesis and properties of high oil‐absorbent 4‐tert‐butylstyrene‐EPDM‐divinylbenzene graft terpolymer

The graft crosslinking polymerization of 4‐tert‐butylstyrene (tBS) and divinylbenzene (DVB) onto ethylene–propylene–diene (EPDM) was carried out in toluene by using benzoyl peroxide (BPO) as an initiator. The synthesized graft terpolymer, tBS‐EPDM‐DVB (PBED), was extracted with tetrahydrofuran (THF) into gel (called as PBED I) and sol, and then they were identified by infrared (IR) spectroscopy. The effects of solvent amount, molar ratio of DVB to tBS, EPDM content, initiator concentration, reaction temperature, and reaction time on the graft crosslinking polymerization were examined. Among them, solvent amount and molar ratio of DVB to tBS were the important factors for this reaction system. Maximum oil absorbency of PBED I was 84.0 g/g but its oil‐absorption kinetic rate was very low. Sol PBED can be reused as oil absorbent (named as PBED II) through photocrosslinking by ultraviolet light irradiation. Although the oil absorbencies of PBED II were lower than those of PBED I in most cases, their oil absorption kinetic rates were higher than oil absorbencies of PBED I. The highest value of oil absorbency of PBED II was 56.0 g/g. The thermal stability of PBED I was studied by TGA. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2119–2129, 2002     

Swelling kinetics of linseed oil‐based polymers

Kinetics of swelling and sorption behavior of copolymers (based on linseed oil, styrene, divinylbenzene, and acrylic acid via cationic and thermal polymerization) is studied in tetrahydrofuran (THF) at different temperatures. The values of n in the transport equation are found to be below 0.4, showing non‐Fickian or pseudo‐Fickian transport in the polymers. The dependence of diffusion coefficient on the composition and temperature has also been studied for the linseed oil‐based polymers. The diffusion coefficient in cationic samples decreases with an increase in the oil contents in the samples. In case of thermal samples, the diffusion coefficient first increases up to 30% oil contents and then decreases. The diffusion coefficient decreases with an increase in temperature for all of the linseed oil polymer samples. The sorption coefficient increases with an increase in the oil contents for all samples. The crosslink density (calculated from the THF swelling) ranges from 20.16 to 92.34 × 10⁶ mol/cm³ for cationic samples and 20.62 to 86.01 × 10⁶ mol/cm³ for thermal samples. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and properties of Mahua oil‐based liquid crystalline pentalkyds

Medium oil length Mahua oil‐based pentalkyds are prepared with varying degree of excess hydroxyl. These alkyds are subsequently converted into liquid crystalline form by copolymerizing with p‐hydroxy benzoic acid (p‐HBA). Esterification is facilitated by dicyclohexyl carbodiimide (DCC). Graft efficiencies of copolymers are calculated and reported. Characterization of grafted alkyds is carried out using IR, DSC, and polarizing microscope techniques. A sharp melting point indicates liquid crystalline characteristic of p‐HBA grafted alkyds. DSC and polarizing microscope study results further substantiated the observation. Mechanical film properties of LC resins viz., hardness, impact resistance, and adhesion are also reported and compared with the amorphous counterparts. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and characterization of highly stable monodisperse argan oil‐in‐water emulsions using microchannel emulsification

Argan oil is well known for its nutraceutical properties. Its specific fatty acid composition and antioxidant content contribute to the stability of the oil and to its dietetic and culinary values. There is an increasing interest to use argan oil in cosmetics, pharmaceutics, and food products. However, the formulation of highly stable emulsions with prolonged shelf life is needed. In this study, argan oil‐in‐water (O/W) emulsions were prepared using microchannel (MC) emulsification process, stabilized by different non‐ionic emulsifiers. The effects of processing temperature on droplet size and size distribution were studied. Physical stability of argan O/W emulsions was also investigated by accelerated stability testing and during storage at room temperature (25 ± 2°C). Highly monodisperse argan O/W emulsions were produced at temperatures up to 70°C. The obtained emulsions were physically stable for several months at room temperature. Furthermore, emulsifier type, concentration, and temperature were the major determinants influencing the droplet size and size distribution. The results indicated that a suitable emulsifier should be selected by experimentation, since the interfacial tension and hydrophilic–lipophilic balance values were not suitable to predict the emulsifying efficiency. Practical applications: MC emulsification produces efficiently monodisperse droplets at wide range of temperatures. The findings of this work may be of great interest for both scientific and industrial purposes since highly stable and monodisperse argan oil‐in‐water emulsions were produced which can be incorporated into food, cosmetic, or pharmaceutical formulations.