Question: what kind of polymers are prepared by addition reactions of alkenes
[{'answer': 'polyolefins', 'provenance': [{'wikipedia_id': '463044', 'title': 'Addition polymer', 'start_paragraph_id': 3, 'start_character': 144, 'end_paragraph_id': 3, 'end_character': 155, 'bleu_score': 1.0, 'section': 'Section::::Polyolefins.\n'}]}, {'provenance': [{'wikipedia_id': '463044', 'title': 'Addition polymer', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 268, 'bleu_score': 0.950578622812921, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10278093638700839674}, 'section': 'Section::::Polyolefins.\n'}]}]