Methods of controlling polymer properties

A method for altering the composition distribution of an ethylene alpha olefin copolymer, the method comprising contacting a reaction mixture and a catalyst system comprising a hafnocene in a fluidized bed gas phase reactor operated at a reactor pressure of between 500 and 5000 kPa, and a reactor temperature of from 50° C. and 120° C., wherein the reaction mixture comprises ethylene, hydrogen, at least one condensing agent, and one or more alpha olefins, and wherein the composition distribution of the copolymer is altered by altering at least one or more of the following:

• a. the molar ratio of hydrogen to ethylene by 1% or more;
• b. the molar ratio of comonomer to ethylene by 1% or more;
• c. the partial pressure of ethylene by 50 kPa or more;
• d. the temperature by 1° C. or more;
• and
• e. the amount of the condensing agent by 1% by mole or more.

A method of forming a first and a second ethylene alpha-olefin copolymer, the method comprising contacting a reaction mixture, the reaction mixture comprising ethylene, hydrogen, and one or more alpha olefins, and a catalyst system comprising a hafnocene, and altering at least one or more of the following:

• i) the molar ratio of hydrogen to ethylene,
• ii) the molar ratio of comonomer to ethylene,
• iii) the ethylene partial pressure and,
• iv) the reactor temperature;
• so that the first ethylene alpha-olefin copolymer has a monomodal composition distribution characterized by having a single peak in a TREF experiment and the second ethylene alpha-olefin copolymer has a multimodal composition distribution characterized by having at least two peaks in a TREF experiment.

A method of forming a first and a second ethylene alpha-olefin copolymer, the method comprising contacting a reaction mixture, the reaction mixture comprising ethylene, hydrogen, and one or more alpha olefins, and a catalyst system comprising a hafnocene, and altering at least one or more of the following:

• i) the molar ratio of hydrogen to ethylene,
• ii) the molar ratio of comonomer to ethylene,
• iii) the ethylene partial pressure and,
• iv) the reactor temperature;
• so that the T90 value of the first ethylene alpha-olefin copolymer and the second ethylene alpha-olefin copolymer differ by 5° C. or more.

A method of forming a first and a second ethylene alpha-olefin copolymer, the method comprising contacting a reaction mixture, the reaction mixture comprising ethylene, hydrogen, and one or more alpha olefins, and a catalyst system comprising a hafnocene, and altering at least one or more of the following:

• i) the molar ratio of hydrogen to ethylene,
• ii) the molar ratio of comonomer to ethylene,
• iii) the ethylene partial pressure and,
• iv) the reactor temperature;
• so that the T75-25 value of the first ethylene alpha-olefin copolymer and the second ethylene alpha-olefin copolymer differ by 5° C. or more.

A method of forming a first and a second ethylene alpha-olefin copolymer, the method comprising contacting a reaction mixture, the reaction mixture comprising ethylene, hydrogen, and one or more alpha olefins, and a catalyst system comprising a hafnocene, and altering at least one or more of the following:

• i) the molar ratio of hydrogen to ethylene,
• ii) the molar ratio of comonomer to ethylene,
• iii) the ethylene partial pressure and,
• iv) the reactor temperature;
• so that the T75-25 value of the first ethylene alpha-olefin copolymer and the second ethylene alpha-olefin copolymer differ by 10° C. or more.