Polymer, separator, and related secondary battery and electric apparatus

A method for preparing polymer granules, comprising:

• providing a first monomer, a second monomer, and a third monomer;
• and
• mixing the first monomer, the second monomer, and the third monomer, and polymerizing them under the action of an initiator to produce the polymer;
• wherein the first monomer comprises a compound represented by formula (IV):
• wherein
• in formula (IV), R1 comprises one or more of hydrogen atom and substituted or unsubstituted C1-C5 alkyl;
• and
• R2 comprises one or more of substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, and substituted or unsubstituted C1-C20 hydroxyalkyl;
• the second monomer comprises a compound represented by formula (V):
• wherein
• in formula (V), R3 comprises one or more of hydrogen atom and substituted or unsubstituted C1-C5 alkyl;
• and
• the third monomer comprises a compound represented by formula (VI):
• wherein
• in formula (VI), R30 to R37 each independently comprise a substituted or unsubstituted C1-C10 alkyl, or a structural unit represented by formula (VI-1), with the proviso that at least one of R30 to R37 comprises the structural unit represented by formula (VI-1):
• wherein
• in formula (VI-1), R12 comprises one or more of hydrogen atom and substituted or unsubstituted C1-C5 alkyl;
• and
• R13 comprises substituted or unsubstituted C1-C10 alkyl wherein a volume distribution particle size Dv50 of the polymer granules satisfies 0.1 μm≤Dv50≤2.0 μm.