I kēia mau lā, ua nīnau kekahi mea kūʻai i ke kumu kūʻai o ke kaula polypropylene, ʻo ka mea kūʻai aku he mea hana i nā ʻupena lawaiʻa i waho, ʻo ka mea maʻamau ka polyethylene kaula, akā ʻoi aku ka maʻalahi o ke kaula polyethylene, maʻalahi e wehe ma hope o ka hoʻopaʻa ʻana, a ʻo ka pōmaikaʻi o ke kaula uea pālahalaha ʻo ia ka ʻOka monofilament o ke kaula, ʻaʻole maʻalahi ka paheʻe ʻana.Akā ʻoi aku ka kaumaha o ka polypropylene ma mua o ka polyethylene.Ma ke kumumanaʻo, ʻo ka molecular formula o propylene ʻo CH3CH2CH3, a ʻo ka molecular formula o ethylene ʻo CH3CH3.ʻOi aku ka nui o ka polypropylene ma mua o ka polyethylene, no laila ʻoi aku ke kaumaha o ke kaula polypropylene ma mua o ka polyethylene.

ʻO ke ʻano o ka polyethylene penei:

—(CH2-CH2-CH2-CH2)n—-

ʻO ke ʻano o ka polypropylene penei:

—(CH2-CH(CH3)-CH2-CH(CH3)-CH2-CH(CH3))n—-

Hiki ke ʻike ʻia ma ke ʻano he kaulahao lālā ka polypropylene ma mua o ka polyethylene.Ma hope o ka hana ʻana i kahi kaula, ma muli o ke kuleana o ke kaulahao lālā, ʻoi aku ka ikaika o ke kaula o ka polypropylene ma mua o ka polyethylene, a ʻaʻole maʻalahi ka paheʻe.He 0.91 ka nui o ka polypropylene a he 0.93 ka nui o ka polyethylene, no laila e kaumaha ka polyethylene.

ʻOi aku ka maʻalahi, ʻoi aku ka maʻalahi o ke kaula polyethylene ma mua o ka polypropylene.