• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3295-3305
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• 2011

Thermal behavior of poly (methyl methacrylate) was analyzed in the presence of tin (IV) chloride. Five different proportions - polymer to additive - were selected for casting films from common solvent. TG, DTG and DTA were employed to monitor thermal degradation of the systems. IR and py-GC-MS helped identify the decomposition products. The blends start degrading at a temperature lower than that of the neat polymer and higher than that of the pure additive. Complex formation between tin of additive and carbonyl oxygen (pendent groups of MMA units) was noticed in the films soon after the mixing of the components in the blends. The samples were also heated at three different temperatures to determine the composition of residues left after the expulsion of volatiles. The polymer, blends and additive exhibited a one step, two-step and three-step degradation, respectively. $T_0$ is highest for the polymer, lowest for the additive and is either $60^{\circ}C$ or $70^{\circ}C$ for the blends. The amount of residue increases down the series [moving from blend-1 (minimum additive concentration) to blend-5 (maximum additive concentration)]. For blend-1, it is 7% of the original mass whereas it is 16% for blend-5. $T_{max}$ also goes up as the concentration of additive in the blends is elevated. The complexation appears to be the cause of observed stabilization. Some new products of degradation were noted apart from those reported earlier. These included methanol, isobutyric acid, acid chloride, etc. Molecular-level mixing of the constituents and "positioning effect" of the additive may have brought about the formation of new compounds. Routes are proposed for the appearance of these substances. Horizontal burning tests were also conducted on polymer and blends and the results are discussed. Activation energies and reaction orders were calculated. Activation energy is highest for the polymer, i.e., 138.9 Kcal/mol while the range for blends is from 51 to 39 Kcal/mol. Stability zones are highlighted for the blends. The interaction between the blended parts seems to be chemical in nature.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.504-510
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• 1996

Low-density polyethylene(LDPE)/Linear low-density polyethylene(LLDPE) blends were prepared by the compositional quenching process, a new morphology control method. The blends were characterized in terms of melting and crystallization behavior and mechanical properties. The results were compared with those of mechanically blended and solution blended samples. From DSC experiments, it was found that the melting temperatures and crystallization temperatures of the blends were dependent on the blending methods. In thermal property, LDPE/LLDPE blends prepared by compositional quenching process were similar to the blends prepared by solution blending but different from the blends prepared by mechanical blending. This result is explained to be due to the domain size dispersed in the matrix. The elongation-at-break and tensile strength of the samples blended by compositional quenching showed similar to those of the samples blended by solution blending method but larger than those of samples prepared by mechanical blending. Also, the Young's modulus showed the same trends as elongation-at-break. The tensile strength of the blends prepared by compositional quenching was not as high as the samples prepared by the other two blending methods.

• Polymer(Korea)
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• v.25 no.4
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• pp.521-527
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• 2001

The miscibility, molecular interaction and tensile properties of the blends of poly (${\varepsilon}$-caprolactone) (PCL) with poly(vinyl chloride) (PVC) have been studied. The measured glass transition temperature values of PCL/PVC blends were found to be well fitted by Fox equation. We found that PCL/PVC blends are amorphous up to 23% PCL content. The blends showed the highest Young's modulus and yield strength at 5% PCL content and the highest tensile strength at 11% PCL content. The blends with low contents of PCL(up to 13%) show increased tensile strength and decreased elongation of PCL/PVC blends. Consequently, the antiplasticization phenomenon is observed in the PCL/PVC blends.

• Korean Journal of Food Science and Technology
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• v.25 no.3
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• pp.232-237
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• 1993

The rheological properties of hard red winter, western white and Australian standard white wheat flours and of HRW-WW and HRW-ASW wheat flour blends having the same protein content were studied. Cooking properties of dry noodles prepared from HRW-WW and HRW-ASW wheat flour blends were also investigated. The noodles were prepared with salt and alkaline reagent. The salt and alkaline concentrations used were 1.7% and 0.17%. respectively, based on the weight of wheat flour. The alkaline reagent was an equal mixture of sodium carbonate and potassium carbonate. The HRW-ASW wheat flour blend had higher farinograph absorption and slightly stronger curve than HRW-WW wheat flour blend. Salt decreased the absorption of wheat flours by 2 and of wheat flour blends by 1%. However, alkaline reagent essentially had no effort on farinograph absorption. Salt and alkaline reagent strengthened the dough of wheat floors and wheat flour blends, with the former being more effective. No significant differences in pasting properties between HRW-WW and HRW-ASW wheat flour blends by amylograph were observed. There were no significant differences in rate of increase of weight or volume between noodles prepared from HRW-WW and HRW-ASW wheat flour blends. Alkaline reagent did not affect the weight gain of noodles hut lowered the volume gain. Breaking force of dry noodles and cutting force of cooked noodles were similar between the two noodles. Alkaline reagent increased both the breaking and cutting forces of noodles. Sensory evaluation revealed that the noodles prepared from HRW-WW and HRW-ASW wheat flour blends were slightly different. but not different from each other by preference test.

• Journal of Adhesion and Interface
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• v.4 no.3
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• pp.33-40
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• 2003

In this work, diglycidyl ether of bisphenol A (DGEBA)/polyetherimide (PEI) blends were cured using 4,4-diaminodiphenyl methane (DDM). And the effects of addition of different PEI contents to neat DGEBA were investigated in the thermal properties and fracture toughness of the blends. The contents of contents of containing PEI were varied in 0, 2.5, 5, 7.5, and 10 phr. The cure activation energies ($E_a$) of the cured specimens were determined by Kissinger equation and the mechanical interfacial properties of the specimens were performed by critical stress intensity factor ($K_{IC}$). Also their surfaces were examined by using a scanning electron microscope (SEM) and the surface energetics of blends was determined by contact angles. As a result, $E_a$ and $K_{IC}$ showed maximum values in the 7.5 phr PEI. This result was interpreted in the increment of the network structure of DGEBA/PEI blends. Also, the surface energetics of the DGEBA/PEI blends showed a similar behavior with the results of $K_{IC}$. This was probably due to the improving of specific or polor component of the surface free energy of DGEBA/PEI blends, resulting in increasing the hydrogen bonding of the hydroxyl and imide groups of the blends.

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.282-288
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• 2015

A new energetic thermoplastic elastomer based on the azidated polybutadiene(Az-PBD)/ethylene vinyl acetate copolymer (EVA) blends was prepared, and structure and properties of the blends were invetigated by SEM, DSC, DMA, tensile testing and combustion test. The Az-PBD was synthesized via a two-step process involving the addition reaction of commercially available 1,2-PBD with $Br_2$ and subsequent nucleophilic substitution reaction of the brominated PBD with $NaN_3$. EVA/Az-PBD with 90/10, 80/20, 70/30 (wt/wt) was prepared by a solution blending. SEM, DSC, and DMA results revealed that the blends are partially compatible and Az-PBD is dispersed in continuous EVA matrix. Tensile test showed that modulus and tension set increased while elongation-at-break of the blends decreased with increasing Az-PBD content in the blends, but all the blends showed a elongation at break as high as 700% and a tension set of less than 5%, indicating that the blends are typically elastomeric. Combustion test showed that, with increasing Az-PBD content in the blend, higher energy can be released.

• Polymer(Korea)
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• v.37 no.4
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• pp.420-430
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• 2013

Polymer blends were prepared by solution blending poly(amic acid) (PAA) and poly(o-hydroxy amide) (PHA) having imide groups in the main chain. The polymers and their blends were characterized by using FTIR, FT NMR, DSC, TGA, SEM, XRD, UTM, and LOI. The solubility study revealed that the blends were readily soluble in aprotic solvents such as DMF, DMAc, DMSO, and NMP. The maximum weight loss of the blends occurred in the range of $578-645^{\circ}C$, and the maximum weight loss temperature increased with increasing the PHA content. The PBO/PI blends showed relatively high char yields (i.e. 56-69 wt%). The LOI values of the blends were in the range of 24.5-28.1% and increased with increasing the PHA content. The initial modulus and tensile strength of the blends increased by 57 to 121% and by 67 to 107%, respectively, compared to the values of PAA. Especially the initial modulus and tensile strength of the PHA/PAA=2/8(wt/wt) showed the highest values of 4.87 GPa and 108 MPa, respectively. The PHA domains of $0.03-0.1{\mu}m$ in their size were more or less uniformly dispersed. The interfacial adhesion between PAA and PHA was found to be good.

• Horticultural Science & Technology
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• v.34 no.6
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• pp.886-897
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• 2016

The physical properties of rooting media for the establishment of plugs in a greenhouse are modified according to variations in the greenhouse environment throughout the season. In this study, we established a standard for rooting media for the production of plug seedlings for each growing season (summer, winter and spring fall). Eight types of peatmoss (PM) and 4 types of perlite (PL) commonly used in Korea were collected and blended with the ratio of 7 parts PM to 3 parts PL (v/v) to make 32 different rooting media blends. We determined the total porosity (TP), container capacity (CC), air-filled porosity (AFP), pH, and electrical conductivity (EC) of the 32 media blends, and 6 media blends were selected for seasonal use. We also conducted additional analyses for plant easily available water (EAW), buffering water (BW), cation exchange capacity (CEC), and nutrient contents in the 6 media blends. The TP, CC, and AFP of the 32 media blends ranged from 64.7 to 96.0%, 42.9 to 90.1%, and 1.3 to 27.8%, respectively, indicating that the physical properties were strongly influenced by the type of PM and PL. The pH and EC of the PMs ranged from 2.96 to 3.81 and 0.08 to $0.47dS{\cdot}m^{-1}$, respectively. However, after blending the PM with the PL the pH was raised and the EC was lowered The media blends selected for the summer growing season were Blonde Golden peatmoss (BG) + No. 1 perlite size < 1 mm (PE1) and Latagro 0-10 mm (L1) + No. 2 perlite size 1-2 mm (PE2). These two media blends had 89.8-90.9% of TP, 80.8-81.3% of CC, and 9.0-9.7% of AFP. The media blends selected for the winter growing season were Sfagnumi Turvas (ST) + PE2 and Latagro 20-40 mm (L3) + PE2. These media blends had 79.9-86.7% of TP, 60.4-74.9% of CC, and 11.8-19.6% of AFP. The TP, CC, and AFP of two media blends, BG + No.3 perlite 2-5 mm (PE3) and Orange peatmoss (O) + PE3, selected for the spring and fall growing seasons, respectively, were 85.2-87.3%, 77.9%, and 7.4-9.4%, respectively. The percentage of EAW of the media blends selected for the spring, summer, and winter growing seasons ranged from 24.2-24.9%, 22.0-28.6%, and 18.0-21.8%, respectively, but the percentages of BW were not significantly different among the selected root media blends. The pH, EC, and CEC of the 6 selected media blends ranged from 3.11-3.97, $0.06-0.26dS{\cdot}m^{-1}$, and $97-119meq{\cdot}100g^{-1}$, respectively.

• Proceedings of the Korean Fiber Society Conference
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• 1993.06a
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• pp.78-79
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• 1993

• Elastomers and Composites
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• v.38 no.1
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• pp.38-50
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• 2003

This paper describes recent advances in ultrasonic devulcanization technology and the in.Situ ultrasonic compatibilization of the blends of the immiscible polymers by making copolymers at the interfaus and their vicinities and our understanding of the mechanism of these processes.