Flame-retardant Coating by Alternate Assembly of Poly（vinylphosphonic acid） and Polyethylenimine for Ramie Fabrics

A novel intumescent flame retardant coating,consisting of poly(vinylphosphonic acid)(PVPA) as the acid source and branched polyethylenimine(BPEI) as the blowing agent,was constructed on the surface of ramie fabrics by alternate assembly to remarkably improve the flame retardancy of ramie.The PVPA/BPEI coating on the surface of individual fibers of ramie fabric pyrolyzes to form protective char layer upon heating/burning and improves the flame retardancy of ramie.Thermogravimetric analysis reveals that the PVPA/BPEI-coated ramie fabrics left as much as 25.8 wt% residue at 600 °C,while the control(uncoated) fabric left less than 1.4 wt% residue.Vertical flame test shows that all PVPA/BPEI-coated fabrics have shorter after-flame time,and the residues well preserved the original weave structure and fiber morphology,whereas,the uncoated fabric left only ashes.Microscale combustion calorimetry shows that the PVPA/BPEI coatings greatly reduce the total heat release by as much as 66% and the heat release capacity by 76%,relative to those of the uncoated fabric.     

An enzymatic flow analysis method for the determination of phosphatidylcholine in sediment pore waters and extracts

A sensitive and selective flow injection method for the determination of phosphatidylcholine (PC) in sediment pore waters and extracts is described. It involves the use of phospholipase C, alkaline phosphatase and choline oxidase co-immobilized on controlled pore glass in a packed column reactor. The final product of the enzymatic reaction of phosphatidylcholine is hydrogen peroxide, and this is detected by measuring the chemiluminescence emission resulting from cobalt(II) catalysed reaction with luminol. The flow injection method is rapid (30 injections/h), reproducible (1.4% R.S.D. at 3 μM PC, n = 10) with a detection limit of 0.14 μM (estimated from 3σ_n−1 of the measured blank). A linear calibration response was obtained over a concentration range of 0.5-9 μM (r = 0.999). The method has been applied to the determination of phosphatidylcholine in sediment extracts and sediment pore waters.     

A computer program system for kinetic analysis of non-isothermal thermogravimetric data: I. Data acquisition and preparation for kinetic analysis

FORTRAN software is described which enables the generation of rate of weight change data (DTG) from percentage weight change measurements (TG), obtained under non-isothermal conditions. The program also transposes this information into the dimensionless extent and rate of reaction at unit temperature intervals by means of a cubic spline interpolation. A simple search routine identifies all DTG spikes in the thermogravimetric record, and the temperature and extent of reaction at which the rate attains its maximum value. This total information serves as input data for the kinetic analysis software to be discussed in part II of this communication. An example of the application of this program to the pyrolysis of bituminous coal is presented.     

A computer program system for kinetic analysis of non-isothermal thermogravimetric data: II. Generalized kinetic analysis and application to coal pyrolysis

A FORTRAN program is presented which enables the kinetic analysis of extent and rate of reaction data resulting from transposed experimental TG/DTG data obtained under non-isothermal conditions. This software allows one to perform Arrhenius, Friedman and Kissinger analyses for up to nine different solid-state rate-controlling reactions, including nth order, Avrami-Erofeev, phase boundary movement and diffusional models. Data from an investigation of the pyrolysis of a bituminous coal serve as an example of the application of the program.     

Coupling of enzymatic and immunoassay steps to detect E. coli: a new, highly sensitive tandem technique for the analysis of low levels of bacteria

A tandem technique for the detection of very low levels E. coli within about 2 h is demonstrated. The technique couples the widely employed microbial enzymatic detection methods with an immunoassay step. The bacterial marker enzyme, E. coli β-D-galactosidase, was used in conjunction with synthetic enzyme substrates to produce products that could be measured with a highly sensitive enzyme-labelled immunosorbent assay (ELISA). The commercially available 4-methylumbelliferyl-β-D-galactoside and a newly prepared substrate, 4-methylcoumarin-3-propionate-7-O-β-D-galactoside, were used with an ELISA for 7-hydroxy-4-methylcoumarin to demonstrate the detection of low levels of E. coli. The 2 h test indicates that a few viable bacteria cells could be detected by the tandem procedure. The end point of the test is an ELISA with colorimetric measurement step. The novel approach retains the essential features of the microbial enzymatic detection procedures and provides a highly sensitive detection system that can be used for rapid screening or quantification of viable microbial cells in water samples. The tandem test is generic for commonly employed glycosidases and other marker enzymes for which 4-methylumbillerone substrates are available.