Sulfide-based polymer, film comprising same and method for preparing same

A polymer comprising:

• a first unit represented by the following Chemical Formula 1;
• and
• a second unit represented by the following Chemical Formula 2:
• wherein, in Chemical Formulae 1 and 2, R1 to R9 are the same as or different from each other, and each independently hydrogen;
• deuterium;
• a halogen group;
• a substituted or unsubstituted alkyl group;
• a substituted or unsubstituted cycloalkyl group;
• a substituted or unsubstituted aryl group;
• or a substituted or unsubstituted heterocyclic group, or adjacent substituents bond to each other to form a substituted or unsubstituted aromatic cyclic group;
• a to h are each an integer of 0 to 4, i is an integer of 0 to 8;
• when a to i are 2 or greater, substituents in the parentheses are the same as or different from each other;
• and
• m and n are each an integer of 1 to 1000.