Ngā Tauira Pātai e Matapaki ana i te Whakapūhui Tāpiri
Ko te whakapūhuitanga te tukanga e honoa ai ngā monomer—ngā ngota iti he rite ngā hanganga—hei hanga i ngā ngota nui ake e kiia nei ko ngā pūhui. E rua ngā momo matua o te whakapūhuitanga: te whakapūhuitanga tāpiri me te whakapūhuitanga whakapūtā. Ka matapakihia e tēnei tuhinga tētahi o ēnei momo, te whakapūhuitanga tāpiri, me te arotahi ki ngā tauira me te matapakinga hei whakarato i te māramatanga hohonu ake mō tēnei ariā.
Te Mārama ki te Whakapūhui Tāpiri
Ko te whakapūhui tāpiritanga he tukanga e honoa ai ngā monomer me te kore e ngaro ngā ngota iti pēnei i te wai, te HCl rānei. Ko ngā monomer e uru nui ana ki te whakapūhui tāpiritanga ko ngā alkene me ngā alkene kua whakapūhuitia, he hononga takirua waro-waro (C=C) kei a rātou. Ina tauhohe ēnei monomer, ka whati ngā hononga takirua, ka taea ai e ngā monomer te hono tahi hei mekameka roa.
Ko ngā tauira o ngā pūmua i hangaia mā te tāpiritanga pūmua ko te polyethylene (PE), te polypropylene (PP), te polystyrene (PS), me te polyvinyl chloride (PVC). He mea nui ēnei pūmua katoa i roto i te ahumahi me te oranga o ia rā nā te mea he kaha, he pumau, he whānui hoki ngā whakamahinga.
Tikanga Whakapūhui Tāpiri
Ka taea te wehewehe i te tikanga whakakotahitanga tāpiri kia toru ngā wāhanga matua:
1. Tīmatanga: Ko te wāhanga e hangaia ai ngā rauropi kore utu, ngā katote rānei hei tīmatanga i te tauhohenga.
2. Te Whakatipu: Ko te wāhanga e hono tonu ai ngā monomer hei hanga mekameka roa.
3. Whakamutunga: Ko te wāhanga ka mutu te tauhohenga nā te mea ka honoa ngā mekameka rauropi kore utu e rua, ka tūtaki rānei ngā rauropi kore utu ki tētahi aukati.
Hei whakamārama ake, anei tētahi matapakinga mō ētahi tauira o ngā pātai mō te whakapūhui tāpiritanga.
Ngā Pātai Tauira me te Kōrero
Pātai 1: Te Whakapūhuitanga o te Polyethylene
Pātai: Whakamāramahia te tukanga tāpiri polymerization o te ethylene (C2H4) hei hanga polyethylene (PE), tāpirihia te whārite tauhohenga e puta ana.
Kōrero:
– Te tīmatanga:
Ka taea te whakatinanatanga mā te whakamahi i ngā whakakorikori, i ngā rauropi kore utu rānei. Me kī tātou kei te whakamahi tātou i ngā rauropi kore utu. Ka taea e ngā whakakorikori rauropi pērā i te benzoyl peroxide (C14H10O4) te tuku i ngā rauropi kore utu ina werahia.
\[
C14H10O4 \rightarrow 2C6H5COO^{\cdot}
\]
– Te Whakatipu:
Ka whakaekea e ēnei irahiko ngā here takirua i roto i te monomer etilena, ka puta he irahiko hou ka taea tonu te whakaeke i te monomer e whai ake nei.
\[
R^{\cdot} + CH2=CH2 \rightarrow R-CH2-CH2^{\cdot}
\]
Muri iho, ka tāpiri tonu ngā irahiko i te pito o te mekameka i ngā monomer etilena kia roa ake ai te mekameka.
\[
R-CH2-CH2^{\cdot} + nCH2=CH2 \rightarrow R-(CH2-CH2)_n^{\cdot}
\]
– Whakamutu:
Ka taea te whakamutu mā te whakakotahitanga o ngā mekameka rauropi e rua, mā te tauhohenga rānei i waenga i tētahi rauropi me tētahi aukati.
\[
R-(CH2-CH2)_n^{\cdot} + R-(CH2-CH2)_m^{\cdot} \rightarrow R-(CH2-CH2)_{n+m}-R
\]
Ko te mutunga iho ko te polyethylene (PE), he pūhui i hangaia mā te whakakotahi i ngā monomer ethylene maha (\(n\) ethylene).
Pātai 2: Te Whakapūhuitanga o te Polystyrene
Pātai: E hiahia ana tētahi umanga matū ki te whakaputa i tētahi pūhui mai i te monomer styrene (C8H8). Whakamāramahia te tauhohenga pūhui e puta ana, ā, tuhia te hanganga o te polystyrene.
Kōrero:
– Te tīmatanga:
Pērā i te polyethylene, e hiahiatia ana ngā rauropi kore utu hei tīmata i te tauhohenga. Me kī tātou ka whakamahia e tātou ngā rauropi peroxide.
\[
ROOR \rightarrow 2RO^{\cdot}
\]
– Te Whakatipu:
Ka whakaekea e ngā rauropi kore utu ngā monomer styrene he hononga takirua waro-waro tō rātou.
\[
RO^{\cdot} + C6H5-CH=CH2 \rightarrow RO-C6H5-CH^{\cdot}-CH3
\]
Mā te wāhanga whakatipu ka haere tonu te whakaeke a ēnei matūriki ki ētahi atu monomer styrene.
\[
RO-C6H5-CH^{\cdot}-CH3 + n(C6H5-CH=CH2) \rightarrow RO-(C6H5-CH-CH2)_n-C6H5-CH^{\cdot}-CH3
\]
– Whakamutu:
Ka mutu te hononga ina tūtaki ngā mekameka pūmua matua e rua.
\[
RO-(C6H5-CH-CH2)_n^{\cdot} + RO-(C6H5-CH-CH2)_m^{\cdot} \rightarrow RO-(C6H5-CH-CH2)_{n+m}-RO
\]
Ko te hanganga polystyrene (PS) e hua mai ana he mekameka roa e titoa ana e ngā waeine monomer styrene e tāruarua ana.
Pātai 3: Te Whakapūhuitanga o te Polyvinyl Chloride (PVC)
Pātai: Whakaahuahia te tāpiritanga o te polymerization o te vinyl chloride monomer (C2H3Cl), me te homai tauira o ngā whakamahinga o te polyvinyl chloride (PVC).
Kōrero:
– Te tīmatanga:
Pērā i te tauira o mua, ka puta mai ngā rauropi kore utu i ngā peroxide.
\[
ROOR \rightarrow 2R-O^{\cdot}
\]
– Te Whakatipu:
Ka whakaekea e ngā rauropi kore utu ngā hononga takirua i roto i ngā monomer vinyl chloride.
\[
RO^{\cdot} + CH2=CHCl \rightarrow RO-CH2-CHCl^{\cdot}
\]
Ka haere tonu te whakatipuranga mā te honoa o ngā waeine monomer hei whakaroa i te mekameka.
\[
RO-CH2-CHCl^{\cdot} + nCH2=CHCl \perematau RO-(CH2-CHCl)_n^{\cdot}
\]
– Whakamutu:
Ka mutu te hononga ina honoa ngā mekameka matua e rua.
\[
RO-(CH2-CHCl)_n^{\cdot} + RO-(CH2-CHCl)_m^{\cdot} \rightarrow RO-(CH2-CHCl)_{n+m}-RO
\]
Ko te polyvinyl chloride (PVC) he pūhui e hangaia ana, e whakamahia ana hoki i roto i ngā momo mahi pēnei i ngā paipa wai, ngā taura hiko, me ētahi atu hua kirihou.
Whakamutunga
He tukanga matū nui te whakakotahitanga tāpiritanga polymerization e uru ana ki te whakakotahitanga o ngā monomers me te kore e tukuna ngā ngota iti. Mā te mārama ki ngā tikanga me ngā tauhohenga o te whakakotahitanga tāpiritanga polymerization, pērā i ngā mea e kitea ana i roto i te polyethylene, polystyrene, me te PVC, ka āwhina i a tātou ki te ako me te whakamahi i tēnei mātauranga i roto i te ahumahi me te oranga o ia rā. Mā roto i ēnei tauira me ngā kōrero, ka taea e tātou te whiwhi māramatanga hohonu ake mō ngā tukanga me ngā hua e puta mai ana i te whakakotahitanga polymerization tāpiritanga, tae atu ki ōna tono mahi e pā ana ki te hangarau me te oranga o ēnei rā.
