A target variable analysis unit (11) calculates the triad fractions of monomer units in the composition of a known polymer sample from the copolymerization reactivity ratios of the monomer units to obtain a target variable. A waveform processing unit (12) processes NMR measurements, signals, etc. An explanatory variable analysis unit (13) obtains explanatory variables from the amount of chemical shift and signal strength in the NMR measurements of the known sample. A model generation unit (14) determines the regression equation of the regression model of the target variable and the explanatory variables by partial least squares regression, and obtains regression model coefficients. A sample analysis unit (15) uses the regression model to calculate the triad fractions for an unknown copolymer sample from the amount of chemical shift and signal strength in the NMR measurements of the unknown copolymer sample. By using a copolymer for lithography in which the total of the triad fractions obtained in this way is not more than 20 mole % in the copolymer, a resist composition with excellent solubility and sensitivity can be manufactured.

Methods of controlling olefin polymerization reactor systems are provided herein. In some aspects, the methods include a) selecting n input variables, each input variable corresponding to a process condition for an olefin polymerization process; b) identifying m response variables, each response variable corresponding to a measurable polymer property; c) adjusting one of more of the n input variables in a plurality of polymerization reactions using the olefin polymerization reactor system, to provide a plurality of olefin polymers and measuring each of the m response variables as a function of the input variables for each olefin polymer; d) analyzing the change in each of the response variables as a function of the input variables to determine the coefficients; e) calculating a Response Surface Model (RSM) using general equations for each response variable determined in step d) to correlate any combination of the n input variables with one or more of m response variables; f) applying n selected input variables to the calculated Response Surface Model (RSM) to predict one or more of m target response variables, each target response variable corresponding to a measurable polymer property; and g) using the n selected input variables I.sup.s1 to I.sup.sn to operate the olefin polymerization reactor system and provide a polyolefin product.

Methods and systems for controlling a polymerization reaction in a non-sticking regime are disclosed. An exemplary method includes measuring parameters for the polymerization reaction including a reactor temperature and a concentration of an induced condensing agent (ICA) in a polymerization reactor. An equivalent partial pressure ((P.sub.ICA).sub.equiv) of the ICA is calculated. The polymerization reaction is located in a two dimension space defined by a reactor temperature dimension and a ((P.sub.ICA).sub.equiv) dimension. The location in the two dimensional space is compared to an non-sticking regime, defined as the space between an upper temperature limit (UTL) curve and a lower temperature limit (LTL) curve. The parameters of the polymerization reaction are adjusted to keep the polymerization reaction within the non-sticking regime.

Described herein are methods for continuous solution polymerization. The method may comprise polymerizing one or more monomers and comonomers in the presence of a solvent in a polymerization reactor to produce a polymer solution; determining the composition of the polymer solution exiting the polymerization reactor in an on-line fashion; determining at least one of the critical pressure or critical temperature; comparing the critical pressure and/or critical temperature to the actual temperature of the polymer solution and the actual pressure of the polymer solution; heating or cooling the polymer solution to a temperature within 50° C. of the critical temperature; and passing the polymer solution through a pressure letdown valve into a liquid-liquid separator, where the pressure of the polymer solution is reduced or raised to a pressure within 50 psig of the critical pressure to induce a separation of the polymer solution into two liquid phases.

Systems and methods for monitoring a particle/fluid mixture are provided. The method can include flowing a mixture comprising charged particles and a fluid past a particle accumulation probe. The method can also include measuring electrical signals detected by the probe as some charged particles pass the probe without contacting the probe while other charged particles contact the probe. The measured electrical signals can be manipulated to provide an output. The method can also include determining from the output if the charged particles contacting the probe have, on average, a different charge than the charged particles that pass the probe without contacting the probe.

A process for production of polyisobutylene includes subjecting a reaction admixture comprising isobutylene, a diluent for the isobutylene, which may be isobutane, and a catalyst composition, that may include a BF.sub.3/methanol catalyst complex, to reaction conditions suitable for causing at least a portion of the isobutylene to undergo polymerization to form a polyisobutylene product including polyisobutylene molecules. At least a fraction of the polyisobutylene molecules thus produced have alpha position double bonds and the polyisobutylene product has a number average molecular weight (M.sub.N) and a polydispersity index (PDI). The concentration of the diluent in the reaction admixture may be manipulated to control or change any one or more of (a) the relative size of the fraction, (b) the number average molecular weight of the product, (c) the polydispersity index of the product and (d) the relative size of the portion. The diluent concentration may be held constant to maintain any one or more of such characteristics constant.

A method of forming a compound having the formula:

##STR00001##

includes the reaction:

##STR00002##

n the presence of a base comprising teat-butyl lithium, lithium diisopropylamide, sodium hydroxide, potassium hydroxide, lithium hydroxide, a potassium alkoxide or a sodium alkoxide to achieve a yield of at least 90%, wherein X is a halo atom selected from the group consisting of Cl, Br and I.

Provided is a method of preparing a copolymer which includes 1) initiating polymerization by batch-adding an aromatic vinyl-based monomer and a vinyl cyan-based monomer to a reactor; and 2) performing polymerization by continuously adding an aromatic vinyl-based monomer to the reactor at a predetermined rate after the initiation of polymerization, wherein the continuous addition of the aromatic vinyl-based monomer is initiated when a polymerization conversion rate is 10% or less and terminated when a polymerization conversion rate is between 80 and 90%, and step 2) includes a first temperature phase and a second temperature phase, each of which maintains a constant temperature, wherein a temperature of the second temperature phase is higher than that of the first temperature phase, and thereby a copolymer with a small standard deviation for a vinyl cyan-based unit composition and excellent transparency may be prepared.

The present disclosure provides a method of determining a relative decrease in catalytic efficacy of a catalyst in a test sample of a catalyst solution with unknown catalytic activity. The method includes (a) mixing the test sample with a test solvent to form a test mixture and (b) measuring the increase in the temperature of the test mixture at predetermined time intervals immediately after forming the test mixture. A predetermined feature is used to determine both a test value in the increase in temperature measured in (b) and a control value in a known increase in temperature of a control mixture of the test solvent with a control sample of a control catalyst solution. The relative decrease in catalytic efficacy of the catalyst in the test sample having the unknown catalytic activity is then determined from: Relative Decrease in Catalytic Efficacy=Control Value−Test Value/Control Value.

The present disclosure provides a method of determining a relative decrease in catalytic efficacy of a catalyst in a test sample of a catalyst solution with unknown catalytic activity. The method includes (a) mixing the test sample with a test solvent to form a test mixture and (b) measuring the increase in the temperature of the test mixture at predetermined time intervals immediately after forming the test mixture. A predetermined feature is used to determine both a test value in the increase in temperature measured in (b) and a control value in a known increase in temperature of a control mixture of the test solvent with a control sample of a control catalyst solution. The relative decrease in catalytic efficacy of the catalyst in the test sample having the unknown catalytic activity is then determined from: Relative Decrease in Catalytic Efficacy=Control Value−Test Value/Control Value.