Polyesters from renewable resources: Preparation and characterization

Polyesters were synthesized with monoglycerides prepared from rubber seed oil, a renewable resource. Monoglycerides were obtained by an alcoholysis method from the oil, which was neat or modified by treatments with different amounts of maleic anhydride at 230°C. The polyester resins were subsequently prepared by the condensation polymerization of the monoglycerides with phthalic anhydride. The monoglycerides and resins were characterized by spectroscopic analysis and measurements of the physicochemical properties. The chemical resistance of the polyesters was also studied. The results revealed that the polyesters prepared from the modified monoglycerides possessed better properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3748–3755, 2006     

Synthesis and properties of soluble polypyrrole doped with dodecylbenzenesulfonate and combined with polymeric additive poly(ethylene glycol)

Soluble polypyrrole (PPy) samples advanced in electrical conductivity σ were chemically synthesized with dodecylbenzenesulfonate (DBS) sodium salt as a dopant, with poly(ethylene glycol) (PEG) as an additive, and with ammonium persulfate as an oxidant. The PPy–DBS–PEG samples were soluble in organic solvents (N‐methylpyrrolinone and m‐cresol). The greater the molar percentage ratio was of DBS, the greater the solubility was of synthesized PPy composites (PPy–DBS–PEG). The maximum electrical conductivity at room temperature for PPy–DBS–PEG was 1.02 S/cm, which was in fact the true conductivity of 100/10 (mol %) PPy/DBS. The chemical composition and doping level of PPy–DBS–PEG were determined by elemental analysis. The results of Fourier transform infrared spectroscopy were used for the structural characterization of PPy–DBS–PEG. The scanning electron microscopy results showed that the electrical conductivity was related to the morphology of PPy–DBS–PEG. According to thermogravimetric analysis, PPy–DBS–PEG was more thermostable than PPy–DBS. Electron spin resonance measurements showed that the polaron and bipolaron acted as charge carriers of PPy–DBS–PEG. According to the temperature dependence of the electrical conductivity, PPy–DBS–PEG was a semiconductor and followed the three‐dimensional variable‐range hopping model. The improved electrical conductivity apparently resulted from the reduction of the crosslinking and structural defects of the PPy chains. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1170–1175, 2005     

Chain conditions on \textit{BL}-algebras

The aim of this paper is to solve the open problem appeared in Motamed and Moghaderi (Soft Comput 2012), about the relation between Noetherian (Artinian) $\textit{BL}$ -algebras in short exact sequences. Also, a better theorem to improve its results is suggested. The relation between Noetherian and Artinian $\textit{BL}$ -algebras is found, the concept of length for a filter in $\textit{BL}$ -algebras is introduced and properties of finite length $\textit{BL}$ -algebras are developed. Finally, it is proved that any $\textit{BL}$ -algebra has finite length if and only if be Noetherian and Artinian.     

An Experimental Investigation of Lime Juice Drying in a Pilot Plant Spray Dryer

One of the major problems in spray drying of fruit juices such as lime juice is stickiness and thermoplasticity of their compositions. Lime juice consists of invert sugars and citric acid, which have low glass transition temperatures. Due to this characteristic, the particles stick on the dryer wall upon their collision with it. As a result, drying of these materials is very difficult. In order to solve this problem, various percent of silicon dioxide and maltodextrin (DE5), based on total soluble solid content of lime juice, have been used to reach a suitable drying condition. A cool chamber wall spray dryer was used in this investigation in order to decrease the probability of particles stickiness on the wall. Our investigation revealed that an addition of 10% silicon dioxide and 20% maltodextrin (DE5) to lime juice is the optimum amount for a complete and successful drying of lime juice. Sampling of particles from different longitudinal distances in the dryer tower is carried out to find the particle moisture contents as they fly downward in the dryer. The results show a very fast decrease in entrance moisture contents. Based on our experimental data, the variation of moisture contents are presented as a function of radial distance from central line and longitudinal distance from the entrance region.     

Electrodeposition of catalytically active nickel powders from sulphate baths. I. Effect of bath constituents

A detailed study was made of the influence of the sulphate bath constituents: 0.3 - 0.0125 NiSO₄·7H₂O (I), 0.05 – 0.23 (NH₄)₂SO₄ (II), 0.1 – 0.4 H₃BO₃ (III) and 0.07 – 0.35 mol l^?1 Na₂SO₄·10H₂O (IV) on the electrodeposition of nickel powder. The cathodic polarization, current efficiency, growth morphology, crystallite size and catalytic activity of the electrodeposited nickel powders were affected to different extents by the bath constituents. A highly pure nickel powder characterized by a small crystallite size (776 Å) and moderate catalytic activity was obtained from a bath containing: 0.0125 (I), 0.23 (II), 0.1 (III) and 0.07 mol l^?1 (IV) at a current density of 10 A dm^?2 and electrolysis time 60 min. at 25 °C. Structural studies with a scanning electron microscope are given and a reaction mechanism for the electrolytic powder deposition is discussed.