聚碳酸酯

• 取(take; gather)ASSOCIATIVE
• 乑(many people standing together)ASSOCIATIVE

Many people pulling together to the same place to gather and stay together.

• 石(stone; rock)RADICAL
• 炭(charcoal; coal)PHONO-SEMANTIC

Carbon is a solid substance like stone, essentially charcoal.

• 酉(wine vessel; ferment)RADICAL
• 夋(slow manner; leisurely pace)PHONETIC

Fermenting alcohol produces sourness, which is exactly the character for sour.