Thermometer, polymeric

Polymerizations were performed in a 1-L five-necked separable flask equipped with a thermometer, a reflux cooler, a VAc dropping funnel, an initiator dropping funnel, and a stirrer. In the standard recipe, the flask was first charged with 250 g of aqueous solution containing 25 g of PVA (the degree of polymerization was approximately 1700 and the degree of hydrolysis was 98.8%) and 5 g of water (in the case of the HPO-tartaric acid [TA] system, 5 g of aqueous solution con-... 

SIN s containing 10% elastomer were charged into a 500 ml. resin kettle provided with a nitrogen inlet, thermometer reflux condenser, and a high torque stirrer. Polymerization of the styrene took place with vigorous stirring at 80°C in a constant temperature oven for 24 hours. Subsequent heating to 180-200°C allowed the elastomer portion to fully react. 

Oil-Based SINs. The SINs produced were based on a castor oil polyester-urethane and styrene crosslinked with 1 mole percent of technical grade (55%) divinyl benzene (DVB) (7). This structure may be written poly[(castor oil, sebacic acid, TDI)-SIN-(Styfene, DVB)], poly[(CO,SA,TDI)-SIN-(S,DVB)]. Benzoyl peroxide (BP) (0.48%) was used as the free radical initiator for the styrene and 1,4-tolylene-diisocyanate (TDI) was used as the crosslinker for the polyester prepolymer. A 500 ml resin kettle equipped with a N inlet, condenser, thermometer, and high torque stirrer was used as the polymerization reactor. 

Uses Determining refractive index of minerals paint diluent dyed hexane is used in thermometers instead of mercury polymerization reaction medium calibrations solvent for vegetable oils alcohol denaturant chief constituent of petroleum ether, rubber solvent, and gasoline in organic synthesis. 

Exact temperature control is very important in polymerization reactions, since, among other things, the rate and degree of polymerization are strongly dependent on temperature. For accurate work, for example, for kinetic analysis with a dilatometer, a thermostat filled with water or paraffin oil may be used instead of thermostatting in the normal way with the aid of a contact thermometer and an immersion heater. 

In a 100 ml three-necked flask with stirrer and thermometer 1 mol% of p-toluenesul-fonic acid methyl ester (methyl tosylate) are added to 3 g (0.03 mol) of anhydrous 2-methyl-2-oxazoline.The reaction mixture is stirred under nitrogen at 100-120 °C.The bulk polymerization sets in immediately. After 30 min. the viscous polymer melt is poured in a dish where it solidifies within minutes. After cooling to room temperature about 2 grams are dissolved in 20 ml ethanol and precipitated in 500 ml THF.The collected precipitate is dried under vacuum. 

The polymerization apparatus (see Fig. 3.2) consists of a 11 three-necked flask, fitted with stirrer, thermometer, gas inlet with tap, and gas outlet.On the inlet side the gas stream passes through three wash bottles one as a safety bottle (A), one for the purification of ethylene, filled with 30 ml of petroleum ether (bp 100-140 °C) and 5 ml of diethylaluminum chloride (B),and one filled with molecular sieves 5 A (C).The last of these dries the ethylene further and also serves to trap aluminum hydroxide carried over from B. On the outlet side there are two wash bottles the first is a safety bottle (D), and the second, (E), is filled with 50 ml of dry bis(2-hydroxyethyl) ether (diglycol), and isolates the apparatus from the external atmosphere. 

The polymerization is carried out in a 500 ml four-necked flask, fitted with stirrer, thermometer, adapter, and nitrogen inlet (see Fig.3.3).The individual parts of the apparatus are previously dried for 1 h at 120 °C,and while still hot are assembled as quickly as possible the whole is then evacuated and filled with PjOs-dried nitrogen three times. 

A polymerization unit containing separate glass ampoules of purified w-hexylisocya-nate, the initiator, and a reaction terminator, was connected to a vacuum and then sealed. The reaction conditions were — 98°C and 1 x 10-6 torr with a reaction time between 5 and 15 minutes. To set the reaction temperature, liquid nitrogen was added to methanol contained in a constant temperature bath to freeze the methanol and the temperature measured using a low-temperature thermometer. The initiator, sodium-benzyl phenyl ketone, was obtained by reacting sodium metal with an equivalent amount of benzyl phenyl ketone in THF and used immediately. The terminator consisted of hydrochloric acid-methanol mixture solution. Reaction scoping results are provided in Table 1. 

Polymerization of Butadiene in Presence of PVC. Et2AlCl-Cobalt Compound Catalyst. A suspension of 20 grams of PVC and 18.7 mg (0.03 mmole) of cobalt(II) stearate in 300 ml of chlorobenzene in a three-necked flask equipped with a reflux condenser, Teflon-coated magnetic stirring bar, thermometer, and gas inlet and outlet was stirred at room temperature for 1 hour while nitrogen was bubbled through. The... 

When the gel has polymerized, the comb is removed and wells are flushed thoroughly with deionized (RNase-free) water. At this stage, the gel can be covered with plastic wrap and stored overnight at 4 °C, if desired. The binder clamps (and tape if used) are removed and the gel is placed on the gel box. The upper and lower reservoirs are filled with 1 x THEM and prerun for 30-45 min with the water bath at the desired temperature, making sure that the current is not blocked by ice, precipitate, or air bubbles. The gel temperature can be monitored with a contact thermometer or small thermal probe inside the gel. 

Solvent for vegetable oils, thermometers (low temperature), polymerization, paint dilutor, and used to denature alcohol. 

Synthesis of Siloxane-Polyimide Elastoplastics. In a typical polymerization, a 5-L, three-neck, round-bottom flask equipped with an overhead mechanical stirrer, a Dean-Stark trap with condenser and a nitrogen inlet, and a thermometer was charged with 484.00 g (0.2406 mol) of D2o-DiSiAn, 41.61 g (0.431 mol) of mPD, 19.52 g (3 wt %) of 2-hydroxypyridine, and 2 L of o-dichlorobenzene. The mixture was warmed to 100 °C for 1 h to dissolve the monomers and the catalyst. The polyamic acids precipitated and then redissolved when the mixture was warmed to 150 °C for 2 h. To the oligomer solution was added 99.13 g of BPADA dissolved in 200 mL of o-dichlorobenzene. The mixture was maintained at 150 °C for an additional 2-h period to ensure incorporation of the dianhydride and then warmed to reflux. After approximately 100 mL of a solvent-water mixture had been removed, the solution was maintained at 180 °C for 40 h. The mixture was cooled to room temperature and diluted with 1 L of methylene chloride. Polymer was isolated from the solution by a slow addition of the polymer solution to 4 L of methanol. The resulting slurry was filtered, and the polymer was redissolved in 4 L of methylene chloride, extracted three times with 2 N aqueous HCl to remove catalyst, washed with water, dried with magnesium sulfate, reprecipitated into methanol as before, filtered, and dried in vacuo at 100 °C to obtain 522 g (85%) of a rubbery material with an IV of 0.50 dL/g. IR, NMR, and Si NMR spectroscopic analysis indicated the absence of amic acid functionalities that could be present if imidization is incomplete. 

On the other hand, it should be noted that, the temperature of the fixed bed packing with the D4006 resin was the lowest one, while the temperature of the fixed bed packing with the NKAII resin was in the highest one. That is to say, the weaker the polarity of the polymeric resin was, the lower the temperature of the ed bed corresponding to the resin was. It meant that the dielectric loss factor of the polymeric resin was in proportion to its polarity. It should be mentioned that since a thermocouple or thermometer can not be used to measure directly the temperature of the fixed bed under microwave field. The temperatures of the fixed beds was measured by means of a special thermometer and Microwave workstation MarS purchased from CEM company, US. 

Polymerizations were carried out in three necked fladcs equipped with mechanical stirrer, and thermometer. The flask was placed in a thermostatically controlled bath filled with n-pentane and cooled by liquid nitrc en (IS). Initiator solutions were precooled and added throu a cold jacketed addition futmel to the stirred charges. Reactions were fast and exothermic. 

In a Pasteur pipette loosely place a very small piece of cotton followed by 2.5 g of alumina. Add to the top of the pipette 1.5 mL of styrene and collect 1 mL in a disposable 10 x 75-mm test tube. Add to the tube 50 mg of benzoyl peroxide and a thermometer and heat the tube over a hot sand bath. When the temperature reaches about 135°C polymerization begins and, since it is an exothermic process, the temperature rises. Keep the reaction under control by cautious heating. The temperature rises, perhaps to 180°C, well above the boiling point of styrene (145°C) the viscosity also increases. Pull the thermometer from the melt from time to time to form fibers when a cool fiber is found to be brittle remove the thermometer. A boiling stick can be added to the tube and the polymer allowed to cool. It can then be removed from the tube or the tube can be broken from the polymer. Should the polymer be sticky the polymerization can be completed in an oven overnight at a temperature of about 85°C. 

J) Polymerization of Acetaldehyde. (1) Place 1 ml of pure acetaldehyde in a test tube which is immersed in a freezing mixture. Insert a thermometer in the tube and note the temperature. Place on the tip of the thermometer a trace of concentrated sulfuric acid, remove the tube from the mixture, and stir with the thermometer... 

Use Solvent, especially for vegetable oils low- temperature thermometers calibrations polymerization reaction medium paint diluent alcohol denatu-rant. 

Polymerization. Polymerization was carried out in a 250 mL 3-neck flask, equipped with a mechanical stirrer, a thermometer, and a rubber septum for initiator introduction. ECH, 93.8 g, and EG,... 

Polymerizations. Homopolymer DADMAC-Solution Polymerization. To a 1-L four-neck resin pot equipped with a mechanical stirrer, thermometer, condenser, purge tube, and heat regulating device were added 492 g of 55% aqueous DADMAC monomer. The pH was adjusted to 6.0 with dilute hydrochloric acid, heated to 50°C, and purged with nitrogen for 1 hr while stirring. Then, 0.05% Na4 EDTA (based on weight reaction mix) was added followed by 1.5 X 10 2 mol f-butyl-peroxypivalate/mol monomer. The temperature was maintained at 50°C 2°C for 18 hr, at which time the monomer conversion to polymer leveled off at 95%. The polymer was isolated via acetone precipitation. 

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