Dhawaan, macmiilku wuxuu waydiiyay qiimaha xadhigga polypropylene, macmiilku waa soo saaraha dhoofinta net kalluumeysiga, sida caadiga ah loo isticmaalo waa xadhig polyetylen, laakiin xadhigga polyetylen waa mid aad u jilicsan, fududahay in la furfuro ka dib gunti, iyo faa'iidada xadhig xadhig fidsan waa in monofilament ee xadhiggu waa qallafsan yahay, guntintu ma fududa in la simbiriiro.Laakiin polypropylene ayaa ka culus polyetylen.Aragti ahaan, qaacidada molecular ee propylene waa CH3CH2CH3, qaacidada molecular ee ethylene waa CH3CH3.Polypropylene waxay leedahay hal atom oo kaarboon ah oo ka badan polyetylen, markaa tirada xadhig polypropylene ayaa ka culus polyetylen.

Qaab dhismeedka polyetylen waa sida soo socota:

—(CH2-CH2-CH2-CH2)n—-

Qaab dhismeedka polypropylene waa sida soo socota:

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

Waxaa laga arki karaa qaab-dhismeedka in polypropylene uu leeyahay silsilad laan ka badan polyetylen.Ka dib marka la sameeyo xadhig, sababtoo ah doorka silsiladda laanta, xadhigga polypropylene wuxuu leeyahay xiisad ka xoog badan polyetylen, mana fududa in la simbiriiro.Cufnaanta polypropylene waa 0.91 cufnaanta polyetylen waa 0.93, markaa polyetylenku waa inuu noqdaa mid culus.

Xadhiga polyetylenka ayaa ka dabacsan, ka jilicsan kana jilicsan polypropylene.