An apparatus for determining the specific volume of solid and liquid polymers as a function of pressure (to 2200 kg/cm2) and temperature (30–350 °C) has been constructed. It is based on Bridgman’s bellows method and makes use of a linear variable differential transformer (LVDT) mounted outside the pressure vessel to measure the length changes of the bellows. The off-null output of the LVDT drives a digital indicator, displaying length changes with an accuracy of 0.01 mm, corresponding to a volume change of 10−3 cm3. Typical samples weigh about 2 g. Volume changes of the sample are calculated from the bellows displacement using the pvT properties of the confining mercury, and by using a calibration function determined in a separate experiment. This apparatus is capable of measuring specific volume changes of polymers with an accuracy of 0.001–0.002 cm3/g. Results for a commercial polystyrene in the glassy and liquid states are given.
The equilibria in solutions containing each one of the diamines H2N(CH2)nNH2, with n = 3 (“pn”), n = 4 (“tn”), n = 5 (“cad”), piperazin (“pip”) and triethylenediamine (“enpip”) in presence of an excess of silver nitrate have been investigated. Values are given for the stability constants of the complexes: Ag(pn)+, Ag(tn)+, Ag(cad)+, Ag(pip)+, Ag(enpip)+, the hydrogen complexes: Ag(Hpn)+2, Ag(Htn)+2, Ag(Hpip)+2 and the bimetallic complexes: Ag2(pn)+2, Ag2(pip)+2.
When N,N‐dialkylamide dimethylsulfate adducts are reacted with cyanoacetyl urea or carbethoxy acetyl urea, the corresponding dialkylamino alkylidene derivatives are formed which cyclize to substituted uracils in the presence of a strong base. When the adducts of cyclic amides are used, the lactam ring is opened simultaneously on cyclisation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.