Principal Monomers Research Articles

Polyurethanes reinforced with Spartium Junceum fibers

The search for alternative polymer composites prepared by renewable resources is gaining increasing attention in the industrial sector. Here we prepared new polyurethane (PU) composite foams with high percentages of the natural vegetable fibers Spartium Junceum in conjunction with biodegradable polyethylene glycols (PEGs). The density and mechanical properties of PU foams were investigated. Further characterization of the morphology of these materials was carried out by scanning electron microscopy. Here we show that these properties can be easily tuned by changing the molecular length of PEGs, the weight ratio between the two principal monomers, and the fraction of water added to the reacting mixtures. POLYM. COMPOS., 37:3042–3049, 2016. © 2015 Society of Plastics Engineers

The Production of Polyimide Foam Materials Based on Acrylonitrile and (Meth)Acrylic Acid

A study was made of the influence of the structure and ratio of the principal monomers, and also the microstructure of obtained block copolymers of (meth) acrylonitrile and (meth)acrylic acid, on the formation, in the process of heat treatment, of poly(meth)acrylimide foam materials.

Pulsed feeding strategy is more favorable to medium-chain-length polyhydroxyalkanoates production from waste rapeseed oil.

This article presents the results of production and characterization of medium-chain-length polyhydroxyalkanoates (mcl-PHAs) using Pseudomonas sp. Gl01. Studies have been carried out to find suitable feeding strategies for mcl-PHAs production and, for the first time, to investigate in-depth the properties of biopolyesters obtained under controlled conditions with waste rapeseed oil as a substrate. Up to 44% mcl-PHAs of cell dry weight was produced at 41 h of biofermentor culture by employing pulsed feeding of waste rapeseed oil. GC analysis showed a polymer composition with monomer length of C6 to C12 with C8 and C10 as the principal monomers. The monomeric structure of the extracted polyesters did not depend on the cultivation time and the feeding strategy. Molecular weight of the mcl-PHAs was found to be ranging from 57 to 154 kDa. Thermal analyses showed the obtained mcl-polyhydroxyalkanaotes to be semi-crystalline biopolymer with promising thermal stability, having a glass transition temperature of -38 to -50°C.

Biosynthesis and Characterization of Polyhydroxyalkanoates Copolymers Produced by Pseudomonas putida Bet001 Isolated from Palm Oil Mill Effluent

The biosynthesis and characterization of medium chain length poly-3-hydroxyalkanoates (mcl-PHA) produced by Pseudomonas putida Bet001 isolated from palm oil mill effluent was studied. The biosynthesis of mcl-PHA in this newly isolated microorganism follows a growth-associated trend. Mcl-PHA accumulation ranging from 49.7 to 68.9% on cell dry weight (CDW) basis were observed when fatty acids ranging from octanoic acid (C8∶0) to oleic acid (C18∶1) were used as sole carbon and energy source. Molecular weight of the polymer was found to be ranging from 55.7 to 77.7 kDa. Depending on the type of fatty acid used, the 1H NMR and GCMSMS analyses of the chiral polymer showed a composition of even and odd carbon atom chain with monomer length of C4 to C14 with C8 and C10 as the principal monomers. No unsaturated monomer was detected. Thermo-chemical analyses showed the accumulated PHA to be semi-crystalline polymer with good thermal stability, having a thermal degradation temperature (T d) of 264.6 to 318.8 (±0.2) oC, melting temperature (T m) of 43. (±0.2) oC, glass transition temperature (T g) of −1.0 (±0.2) oC and apparent melting enthalpy of fusion (ΔH f) of 100.9 (±0.1) J g−1.

Chemical composition and dietary fibre of yellow and green commercial soybeans (Glycine max)

Proximate composition and dietary fibre (as non-starch polysaccharides) of yellow soybeans (from conventional, ecological, transgenic and non-transgenic crops) and green soybeans (from conventional and ecological crops) has been studied. Dietary fibre, fat and ash were significantly higher in yellow than in green samples, but moisture and available carbohydrates were significantly lower in yellow soybean than in green ones. Few statistical differences were found for protein between different samples. Soybean seeds were rich in dietary fibre (yellow: 13.7–16.5 g/100 g, green: 9.19–9.45 g/100 g). This component was evaluated as insoluble and soluble fibre, and subsequently, the neutral sugars and uronic acids were determined by gas liquid chromatography and spectrophotometry, respectively. Insoluble fibre became the predominant fibre fraction in yellow and green soybeans (74–78%), and was mainly composed of glucose, uronic acids, galactose, arabinose and xylose. Soluble fibre was between 22% and 26% in both kinds of samples and the principal monomers were uronic acids, galactose and arabinose. The major difference between total dietary fibres of yellow and green commercial samples was the proportion of galactose, which was an important constituent in yellow soybeans (21%) and a minor one in green soybeans (5%).

FUNDAMENTAL STUDY OF PAINT SYSTEMS FOR MOBILE PHONES

The diversity of paint arises from the properties required of a coating. All ideal properties cannot be met in a single product because the paints are are constrained by the nature of the substrate on which the paint is used. The choice of polymer determines the paint film properties and as such, is the most important factor in the formulation of a paint. In this investigation, poly(vinylchloride) (PVC) copolymer with other principal monomers such as acrylic and polyurethane were studied. In addition to mechanical properties, abrading, adhesion, and scratch resistance were studied. Special attention was focused on the chemical resistance to ethanol and artificial perspiration. PVC copolymerization with acrylic or polyurethane was found to significantly enhance the chemical resistance of the basic binder system. In the free-radical polymerization process of PVC, it improved the physical properties of the paint system in terms of its permeability to acid. This prevents corrosion of aluminum flakes in the metallic paint used for mobile phones.

On-Line Monitoring of Emulsion Copolymerisations Using Hardware Sensors and Calorimetry

ABSTRACTWe have used a simplified model of emulsion polymerisation, along with an adaptive calorimetric approach and a set of non-linear state estimators to monitor the individual monomer conversions in a pilot scale polymerisation reactor for the production of methyl methacrylate/butyl acrylate/carboxylic acid polymers. The usefulness of reaction calorimetry for the monitoring of such systems is demonstrated. It is also shown that non-linear, high gain estimators can be used to monitor such systems even if they are based on simplified models that ignore polymerisation of the two principal monomers in the aqueous phase, and of the carboxylic acid. The advantages and disadvantages of several different types of on-line sensors for use in industrial situations are also reviewed.

The composition of maturing Omani dates

The composition of two varieties of Omani dates, fard and khalas, was determined as maturity progressed. Free sugars and dietary fibre content were examined in detail. High-performance liquid chromatography (HPLC) of the extracts showed that at the early green stage (Arabic kimri), dates contained small amounts of glucose and fructose. At the intermediate yellow (khalal) and red (rutab) stages, large amounts (500–565 g kg−1 dry weight) of sucrose had accumulated, but no additional glucose or fructose was detected. At the final mature (tamar) stage, all sucrose was converted to glucose and fructose (>800 g kg−1 dry weight). Dietary fibre, determined as non-starch polysaccharides (NSPs) by gas chromatography (GC), decreased from 250 g kg−1 (kimri) to 50 g kg−1 (tamar) on a dry weight basis. The principal monomers of NSPs were glucose, galactose, xylose, mannose, arabinose and rhamnose. On a dry weight basis, pectin, protein and ash contents decreased as the dates matured. On a fresh weight basis, changes in NSPs, pectin, protein and ash could be attributed to loss of moisture and the accumulation of sucrose initially, or of invert sugar later as maturation progressed. © 1999 Society of Chemical Industry

Polyurethane elastomers with low modulus and hardness based on novel copolyether macrodiols

A series of copolyether macrodiols was prepared from either 1,10-decanediol or 1,6-hexanediol, by acid-catalyzed condensation polymerization using several comonomers to investigate the effect of copolymerization on reducing macrodiol crystallinity. The comonomers used to disrupt crystallinity included 2,2-diethyl-1,3-propanediol, 1,4-cyclohexanedimethanol, and 1,7-heptanediol. The product copolyethers were identified as hydroxy terminated copoly(alkylene oxides) by 1H- and 13C-NMR spectroscopy. Based on NMR results, the structures of the copolyethers were established as consisting of blocks of the principal monomer with comonomer 2,2-diethyl-1,3-propanediol incorporated to form only the end structural unit, whereas 1,4-cyclohexanedimethanol incorporated to form the end unit as well as part of the main chain. DSC results confirmed that the copolymerization produced macrodiols with lower crystallinity and lower Tg than those of the corresponding homopolyethers of the principal monomers, with two exceptions. The exceptions were 1,6-hexanediol/1,10-decanediol, and 1,10-decanediol/1,7-heptanediol copolyethers where no reduction in crystallinity was observed. A series of polyurethane elastomers with a constant hard segment percentage (40 wt %) was prepared using 4,4′-methylenediphenyl diisocyanate and 1,4-butanediol as the hard segment. Tensile test results and Shore hardness measurements demonstrated that copolyether macrodiols produced several polyurethanes with lower modulus and hardness than those of polyurethanes based on homopolyethers of the principal monomers. Of the comonomers studied, 2,2-diethyl-1,3-propanediol-based copolyether produced the polyurethane with the lowest hardness and modulus. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1373–1384, 1997

Effect of crosslinker on properties of copolymeric N‐vinyl‐2‐pyrrolidone/methyl methacrylate hydrogels and organogels

AbstractThe γ‐ray initiated copolymerisation of N‐vinyl‐2‐pyrrolidone with methyl methacrylate in the presence of crosslinker has been effected to high conversion. At two fixed compositions of the principal monomers, the inclusion of different concentrations of the tetrafunctional crosslinkers ethylene dimethacrylate and a low molar mass poly(ethylene glycol) dimethacrylate produced crosslinked xerogels, which were subsequently swollen in water and 1,4‐dioxane to yield hydrogels and organogels, respectively. These gels were characterised by determinations of sol fraction, equilibrium solvent content and uniaxial compression stress/strain measurements. Differences among the swelling and mechanical properties according to the nature and concentration of crosslinking agent and according to the nature of the swelling medium are noted and discussed.

Aromatic/cycloaliphatic polyamide membrane

A new composite hyperfiltration membrane based on an aromatic/cycloaliphatic polyamide is under development. Principal monomers employed are m-phenylenediamine and 1,3,5-cyclohexane tricarbonyl chloride. Characterization of the membrane under standard brackish test conditions indicates superior flux. Performance under test conditions appropriate to some specific applications suggests general utility. Field testing of spirally wound cartridges has started. Preliminary results are encouraging.

Vinyl monomers derived from fats and oils.

AbstractPreparation, properties, and uses of monomers containing saturated or unsaturated C12舑18 fatty radicals derived from fats and oils and capable of polymerization or copolymerization by vinyltype mechanisms are reviewed. Principal monomers discussed are vinyl esters and ethers, acrylic esters, allylic esters and ethers, and ॅ‐olefins.