Pu Products Research Articles

Reinforcement of Castor Oil-Based Polyurethane with Surface Modification of Attapulgite.

Polyurethane/attapulgite (PU/ATT) nanocomposites derived from castor oil were prepared by incorporation of 8 wt % ATT, acid-treated ATT, and KH560-treated ATT. The effects of three ATTs (ATT, acid-ATT, and KH560-ATT) on the comprehensive properties of PU/ATT nanocomposites were systematically investigated. The results showed that the incorporation of 8 wt % of three ATTs could produce an obvious reinforcement on the castor oil-based PU and that the silane modification treatment, rather than the acid treatment, has the more effective reinforcement effect. SEM images revealed the uniform dispersion of ATT in the PU matrix. DMA confirmed that the storage modulus and glass transition temperature (Tg) of PU/ATT nanocomposites were significantly increased after blending with different ATTs. For PU/KH560-ATT8 nanocomposites, the thermal stability of the PU was obviously enhanced by the addition of KH560-ATT. In particular, 8 wt % KH560-ATT loaded castor oil-based PU nanocomposites exhibit an obvious improvement in tensile strength (255%), Young’s modulus (200%), Tg (5.1 °C), the storage modulus at 25 °C (104%), and the initial decomposition temperature (7.7 °C). The prepared bio-based PU materials could be a potential candidate to replace petroleum-based PU products in practical applications.

ANALISIS BULLWHIP EFFECT PADA PERENCANAAN KEBUTUHAN MATERIAL BELT CONVEYOR

Controlling the supply of raw materials belt conveyor is a very important management function because it is a vital company investment, both in terms of value and future prospects. Well-implemented inventory control management can trigger a company's success in production. In manufacturing companies there is often a delay in the arrival of material arrival due to various things, such as the bullwhip effect between the company with suppliers, companies with distributors or companies with buyers. The focus of this research is to know how big the occurrence of bullwhip effect and how to decrease the bullwhip effect that already happened. From the calculation results obtained a decrease in the value of the bullwhip effect from the original to PU White products 2,786 to 1,524, blue PU products 3,297 to 1,455, and PVC Green 2.025 to 1.5794.

Reaction‐induced phase separation in hexamethylene diisocyanate‐based poly(propylene oxide)/poly(ethylene oxide) bi‐soft segment oligomers

AbstractOligomeric bi‐soft segment isocyanate‐terminated polyurethanes (ITPUs) are semi‐finished materials crucial for the synthesis of various PU products like foams, thermoplastic parts, dispersions or elastomers. Incompatibilities and thus phase separation phenomena play an essential role in tailoring the properties of the final products. Therefore, a detailed knowledge of these phenomena is mandatory in order to design products with properties meeting the requirements of a given application. In this study the reaction‐induced phase separation during the formation of ITPUs by application of two partially miscible soft segments is presented. The physicochemical basics of this process as well as the extent of the resulting phase separation are discussed on the basis of the initial phase diagram of the reactants. Reaction monitoring by NCO content titration and UV–visible spectroscopy reveals a dependency between the onset of phase separation and conversion. It is found that an increase of the initial content of hexamethylene diisocyanate delays the onset of phase separation. Differential scanning calorimetry reveals further that the phase separation is a direct consequence of the incompatibility of the soft segments. Overall, the findings support the hypothesis that the mechanism and the extent of phase separation are closely related to the ternary phase diagram of the reactants. © 2018 Society of Chemical Industry

Dissociation of diglycolamide complexes of Ln3+ (Ln = La-Lu) and An3+ (An = Pu, Am, Cm): redox chemistry of 4f and 5f elements in the gas phase parallels solution behavior.

Tripositive lanthanide and actinide ions, Ln(3+) (Ln = La-Lu) and An(3+) (An = Pu, Am, Cm), were transferred from solution to gas by electrospray ionization as Ln(L)3(3+) and An(L)3(3+) complexes, where L = tetramethyl-3-oxa-glutaramide (TMOGA). The fragmentation chemistry of the complexes was examined by collision-induced and electron transfer dissociation (CID and ETD). Protonated TMOGA, HL(+), and Ln(L)(L-H)(2+) are the major products upon CID of La(L)3(3+), Ce(L)3(3+), and Pr(L)3(3+), while Ln(L)2(3+) is increasingly pronounced beyond Pr. A C-Oether bond cleavage product appears upon CID of all Ln(L)3(3+); only for Eu(L)3(3+) is the divalent complex, Eu(L)2(2+), dominant. The CID patterns of Pu(L)3(3+), Am(L)3(3+), and Cm(L)3(3+) are similar to those of the Ln(L)3(3+) for the late Ln. A striking exception is the appearance of Pu(IV) products upon CID of Pu(L)3(3+), in accord with the relatively low Pu(IV)/Pu(III) reduction potential in solution. Minor divalent Ln(L)2(2+) and An(L)2(2+) were produced for all Ln and An; with the exception of Eu(L)2(2+) these complexes form adducts with O2, presumably producing superoxides in which the trivalent oxidation state is recovered. ETD of Ln(L)3(3+) and An(L)3(3+) reveals behavior which parallels that of the Ln(3+) and An(3+) ions in solution. A C-Oether bond cleavage product, in which the trivalent oxidation state is preserved, appeared for all complexes; charge reduction products, Ln(L)2(2+) and Ln(L)3(2+), appear only for Sm, Eu, and Yb, which have stable divalent oxidation states. Both CID and ETD reveal chemistry that reflects the condensed-phase redox behavior of the 4f and 5f elements.

Emissions of amides (N,N-dimethylformamide and formamide) and other obnoxious volatile organic compounds from different mattress textile products

The emission rates of N,N-dimethylformamide (DMF), formamide (FAd), and certain hazardous volatile organic compounds (VOCs) were measured from seventeen mattress textile samples with four different raw material types: polyurethane (PU: n=3), polyester/polyethylene (PE: n=7), ethylene vinyl acetate (EV: n=3), and polyvinyl chloride (PC: n=4). To simulate the emissions in a heated room during winter season, measurements were made under temperature-controlled conditions, i.e., 50°C by using a mini-chamber system made of a midget impinger. Comparison of the data indicates that the patterns were greatly distinguished between DMF and FAd. PU products yielded the highest mean emission rates of DMF (2940μgm−2h−1: n=3) followed by PE (325μgm−2h−1: n=7), although its emission was not seen from other materials (EV and PC). In contrast, the pattern of FAd emission was moderately reversed from that of DMF: EV>PC>PE>PU. The results of our analysis confirm that most materials used for mattress production have the strong potential to emit either DMF or FAd in relatively large quantities while in use in children׳s care facilities, especially in winter months. Moreover, it was also observed that an increase in temperature (25°C to 50°C) had a significant impact on the emission rate of FAd and other hazardous VOCs. In addition to the aforementioned amides, the study revealed significant emissions of a number of hazardous VOCs, such as aromatic and carbonyl compounds.

Polyols and polyurethanes prepared from epoxidized soybean oil ring‐opened by polyhydroxy fatty acids with varying OH numbers

AbstractBio‐based polyols from epoxidized soybean oil and different fatty acids were successfully prepared using a solvent‐free method in order to investigate the effect of the polyols' OH numbers on the thermal and mechanical properties of the polyurethanes prepared using them. Epoxidized soybean oil/epoxidized linseed oil was ring‐opened by methanol/glycol followed by saponification to prepare polyhydroxy fatty acids. These fatty acids and epoxidized soybean oil were then used for further solvent‐free ring‐opening reactions with DBU as catalyst, which facilitated the carboxylic ring‐opening. Gel permeation chromatography revealed that a molar ratio of carboxylic acid from polyhydroxy fatty aicds and epoxy group of 0.5 : 1 resulted in optimized polyols containing the smallest amounts of residual starting materials. The obtained polyols had varying OH numbers and the acquired polyurethane films were comprehensively characterized. With increasing OH number of the polyols the PUs displayed an increase in crosslinking density, glass transition temperature (Tg), tensile strength and Young's modulus, and a decrease in elongation and toughness. This work provides Supporting Information on the effect of OH number of polyols obtained via a solvent‐free ring‐opening method on the mechanical and thermal properties of polyurethanes, of particular interest when designing PU products for specific purposes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41213.

Single-Stage Dual-Column HPLC Technique for Separation and Determination of Lanthanides in Uranium Matrix: Application to Burnup Measurement on Nuclear Reactor Fuel

A single-stage dual-column chromatographic technique has been developed in this study for separation and determination of lanthanides in a uranium matrix. A 5-cm-length reversed-phase column coated with tri-n-octylphosphine oxide (TOPO) was connected in series to a 10-cm-length reversed-phase monolithic column (dynamically modified into a cation exchange column) to accomplish individual isolation of lanthanides from the uranium matrix. The proposed technique eliminates the step of uranium matrix removal for the determination of lanthanides. Samples with a lanthanide-to-uranium ratio (1 part lanthanide to 105 parts uranium) were directly injected into the dual column for the quantitative determination of lanthanides without uranium matrix removal. In some studies, samples of lanthanides in the uranium matrix could be injected as much as 45 times consecutively into a high-performance liquid chromatography system for determination of lanthanides without any uranium elution. The retention behavior of Pu(IV), Pu(III), Am(III), and fission products was also investigated on the TOPO-coated support. The single-stage dual-column chromatographic technique was demonstrated for the determination of fission products such as La and Nd in the dissolver solution of pressurized heavy water reactor spent fuel for the measurement of atom percent fission burnup. The technique can also be employed to estimate lanthanide impurities in samples of UO2 (1 part lanthanide to 106 parts uranium) without removal of the uranium matrix.

Waterborne Polyurethane: Effect of Functional Groups in Aromatic Isocyanate and the Chain Length of Hydroxyl Terminated Natural Rubber

Waterborne polyurethane (WPU) has its main applications in coatings and adhesives. Compared with the competing PU products from solvent-based processes, it has a more environmentally friendly manufacturing process. Its economic competitiveness could also be improved by the use of aromatic isocyanates that are widely available and cheaper than the currently used aliphatic isocyanates. We report on the synthesis and properties of WPU, based on natural rubber (NR) whose molecular structure has been altered, in combination with an aromatic isocyanate. The NR modification is by hydroxyl termination, with experiments using two chain lengths (HT600 and HT1000, named after molecular weight). The aromatic isocyanates used are 4,4’-Methylene bis (phenyl isocyanate) (MDI) and polymethylene polyphenyl polyisocyanate (p-MDI). The synthesized chemical structure is characterized using ATR-FTIR, while the key material properties reported here are the pH value, mean particle size and size distribution, and glass transition temperature. The WPU achieved suitable material properties, with small particles sizes and good dispersion, for applications in coatings.

Radiolytic Degradation Studies on N,N‐dihexyloctanamide (DHOA) under PUREX Process Conditions

The radiolytic stability of DHOA, a high molecular weight N,N‐dialkyl amide has been investigated to evaluate its performance under PUREX process conditions vis–a–vis TBP. Gas chromatographic studies revealed the presence of caprylic acid, dihexylamine and dihexylketone in irradiated DHOA. Batch distribution studies of Pu, U, and fission products (144Ce, 103,106Ru, and 137Cs) were carried out using the irradiated samples of 1.1 M DHOA and TBP in n‐dodecane, which showed significant retention of Pu, U, and fission products in the irradiated TBP as compared to that of DHOA even after successive contacts with the stripping solutions. Typically at 60 M Rad dose, the Pu content for DHOA was 1.4 mg/L after three contacts with 0.5 M HNO3, and that for TBP was ∼24 mg/L. White precipitate was observed at the interface during the stripping of Pu (with 0.5 M HNO3) from the loaded irradiated TBP phase. The DHOA system, on the other hand showed no such problem during the stripping cycle but there was an increase in the density and viscosity for the irradiated DHOA.

PU chemicals and products in Europe, Middle East & Africa (EMEA), 2007

PU chemicals and products in Europe, Middle East & Africa (EMEA), 2007

Síntese e caracterização de poliuretanos segmentados contendo blocos de peso molecular controlado. Parte 2: correlações entre morfologia e comportamentos térmico e mecânico

Poliuretanos segmentados formados por segmentos flexíveis e rígidos bem caracterizados foram sintetizados através de uma nova metodologia de síntese, em que cada segmento foi preparado separadamente, e ambos acoplados em uma etapa posterior (produtos SPU). Uma outra série de poliuretanos segmentados similares em composição foi obtida pelo método tradicional em duas etapas (produtos PU). As propriedades térmicas e mecânicas destes materiais foram determinadas por calorimetria diferencial de varredura e ensaios de tensão-deformação. As duas séries de polímeros apresentaram diferenças marcantes no comportamento térmico e desempenho mecânico, as quais foram atribuídas à diferenças em morfologia. Os resultados observados foram interpretados em termos de tamanho e polidispersão dos segmentos rígidos e flexíveis. Microscopia eletrônica de varredura e calorimetria diferencial de varredura mostraram que os produtos SPU possuíam separação de fases mais acentuada do que os produtos PU. Espalhamento de raios X sob alto ângulo confirmaram estes resultados.

Cloning and molecular characterization of a metabolic gene with development functions in Drosophila. I. Analysis of the head function of Punch.

In an effort to understand the functions of pterins throughout development we have been studying Punch (Pu), the structural gene for the enzyme GTP cyclohydrolase in Drosophila melanogaster. This enzyme catalyzes the first step in the pterin biosynthetic pathway. The Pu gene product is required for vital functions at two distinct stages in embryogenesis, and a pigmentation function in the eye of the young adult. We have localized the Pu region to 29 kb of DNA through the analysis of lesions present in Pu mutants. Since all of the mutations that were mapped affect the eye pigmentation function of Pu, and since this function is the best defined biochemically, we have concentrated on identifying and characterizing Pu products required for eye pigmentation in our initial examination of the cloned region. Four different transcripts from this region are expressed in the adult head. We show that one of these transcripts, the 1.7-kb species, is responsible for the pigmentation function through the analysis of mutant transcripts and the use of an in vitro translation assay. A 2-kb region lying within the locus is specifically required for this eye pigmentation function.

Low-Temperature Partitioning of Plutonium with High U(VI)-Loading for Fuel Reprocessing

Measurement of the distribution ratios of Pu(IV), U(VI) and HNO3 at low temperatures and its treatment with DIST code revealed that a high U (VI)-loading of 30% TBP in n-dodecane splits Pu(IV) down to the aqueous phase more strongly than do at 25°C. Based on these findings, flowsheet conditions to separate Pu(IV) from U(VI) were investigated with EXTRA.M code including the distribution equations obtained above. And tentative flowsheets for non-reductive Pu-splitting process at a temperature of 5°C were proposed for fuel reprocessing mainly based on the effects of U (VI)-loading in the solvent and temperature on distribution ratios of Pu(IV) and U(VI). Distribution ratios of the fission products, Zr, Nb, Ru and Ce were also measured to assess their decontamination from U or Pu products in the above process. Finally behavior of Np, in the proposed partitioning process was discussed by analysis with EXTRA. M code and a redox reaction model.

Low-temperature partitioning of plutonium with high U(VI)-loading for fuel reprocessing.

Measurement of the distribution ratios of Pu(IV), U(VI) and HNO3 at low temperatures and its treatment with DIST code revealed that a high U (VI)-loading of 30% TBP in n-dodecane splits Pu(IV) down to the aqueous phase more strongly than do at 25°C. Based on these findings, flowsheet conditions to separate Pu(IV) from U(VI) were investigated with EXTRA.M code including the distribution equations obtained above. And tentative flowsheets for non-reductive Pu-splitting process at a temperature of 5°C were proposed for fuel reprocessing mainly based on the effects of U (VI)-loading in the solvent and temperature on distribution ratios of Pu(IV) and U(VI). Distribution ratios of the fission products, Zr, Nb, Ru and Ce were also measured to assess their decontamination from U or Pu products in the above process. Finally behavior of Np, in the proposed partitioning process was discussed by analysis with EXTRA. M code and a redox reaction model.