Alkylketene dimers

Fig. X-6. Drop of water on an alkylketene dimer surface (rt) fractal surface D (b) flat surface. (From Ref. 68.)...

CTD.ORINE OXYGEN ACIDS AND SALTS - DICTD.ORINE MONOXIDE, HYPOCTD.OROUS ACID, AND HYPOCm ORITES] (Vol 5) Alkylketene dimers (AKD)... 

The higher, long-chain dimers as weH as the tetramer dehydroacetic acid are far more stable and can be handled safely. The alkylketene dimers (AKDs) are shipped to the paper industry in tank tmcks in the form of ready-to-use aqueous emulsions with a total soHds content of 12—25% and a guaranteed shelf life of 30 days, as they have good hydrolytic stabHity. In this form they are not combustible Hquids, and are Hsted in the Canadian Domestic Substances List. 

The world production of the alkylketene dimers is beUeved to be around 15,000 metric tons, equaHy spHt between the United States and the rest of the world. The value of the AKDs (80—85% assay) is 4.00-4.40/kg. 

Other Uses. A small but growing oudet for C and higher linear olefins is the production of alkenylsuccinic anhydride (ASA) for the paper iadustry. ASA is an effective alkaline sizing agent and competes with alkylketene dimer (AKD) ia this appHcatioa. 

Alkylketene—dimer emulsion sizes can be appHed to the surface of paper and provide very efficient sizing. Used by themselves, these sizing agents can provide a sHppery surface consequendy, they often are used in conjunction with starch or some filler which reduces sHppetiness without detracting from sizing efficiency. 

Fields and Zopf<< have shown that liquid motor fuels containing n trace of water cease to be corrosive ader treatment with a trace of alkylketene dimer. 

A particular type of cellulose esters are those formed with paper sizing agents such as alkylketene dimers (AKD) or alkenylsuccinic anhydride (ASA) [47], The reaction of cellulose with alkylketene dimers generates p-ketoesters ... 

Aquapel [Hercules]. TM for an alkylketene dimer that is reactive with alkaline cellulose. 

Lindstrom, T. and Soderberg, G., On the mechanism of sizing with alkyl ketene dimers. Part 3, The role of pH, electrolytes, retention aids, extractives, Ca-lignosulfonatos and mode of addition on alkylketene dimer retention, Nord. Pulp Paper Res. J., 1(2), pp. 31-38 (1986). 

Because ablation is carried ont at high temperatures it is possible to examine thermally static polymers snch as poly-p-methylstyrene. Other recent applications of ToF-SIMS include the examination of PS [182-184], PE [185], carbon fibre-reinforced epoxy resins [186], polyalkylacrylates [187], alkylketene dimers [188], perfluorinated polymers [189],... 

Cellulosic fibers can be sized i.e. given hydrophobic properties in various ways. The classical method is using rosin size with the addition of alum. This method does not work for neutral pH where one instead reacts the fibers with alkylketene dimer (AKD). 

Zimmermann et al used time of flight secondary ion mass spectrometry to determine alkylketene dimer in kraft papers. 

Other recent applications of ToF-SIMS without XPS include the examination of PS [6, 17-19], polyethylene (PE) [20], carbon fibre reinforced epoxy resins [21], polyalkyl methacrylates [22], alkylketene dimers [23], perfluorinated polymers [24], perflnorinated ethers [25], polyethylene glycol (PEG) oligomers [15, 25-29], rubber [30], ethylene-tetrafluoroethylene copolymer [30], Nylon-6 [31], PC [32,33], PDMS [34], polypyrrole coated PS [35], poly-p-phenylene vinylene [36], butyl rubber [37], poly(4-vinyl phenol)/poly(4-vinyl pyridine blends) [38], polypyrrole-silica gel composites [39], y-glycidoxypropyl trimethoxy silane [40], triblock copolymer poly(ethylene glycol)- 3 poly(phenylene ethylene)- 3 poly(ethylene glycol) [41], ethylene-terephthalate-hydroxybenzoate copolymer [42], PS-polyvinyl methyl ether, polycarbonate - PS blends [43] and PDMS-urethane [44],... 

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