Lero, ndikuwuzani mwachidule mbiri ya mapulasitiki.

Pulasitiki yoyamba yopangidwa kwathunthu m'mbiri ya anthu inali phenolic resin yopangidwa ndi American Baekeland yokhala ndi phenol ndi formaldehyde mu 1909, yomwe imadziwikanso kuti pulasitiki ya Baekeland.Phenolic resins amapangidwa ndi condensation reaction ya phenols ndi aldehydes, ndipo amakhala a thermosetting mapulasitiki.The ndondomeko kukonzekera lagawidwa masitepe awiri: sitepe yoyamba: choyamba polymerize mu pawiri ndi otsika liniya digiri ya polymerization;sitepe yachiwiri: ntchito kutentha kutentha mankhwala kusintha kukhala polima pawiri ndi mkulu digiri polymerization.
Pambuyo pazaka zoposa zana zachitukuko, zinthu zapulasitiki tsopano zili paliponse ndipo zikupitiriza kukula mofulumira kwambiri.Utoto woyera ukhoza kukhala wopanda mtundu komanso wowonekera kapena woyera m'mawonekedwe, kotero kuti mankhwalawa alibe mawonekedwe owoneka bwino komanso owoneka bwino.Choncho, kupatsa pulasitiki mitundu yowala kwakhala udindo wosalephereka wa makampani opanga mapulasitiki.N’chifukwa chiyani mapulasitiki apangidwa mofulumira chonchi m’zaka 100 zokha?Makamaka chifukwa ali ndi zabwino zotsatirazi:

1. Pulasitiki imatha kupangidwa pamlingo waukulu.(Kupyolera mupulasitiki nkhungu)

2. Kachulukidwe wachibale wa pulasitiki ndi wopepuka ndipo mphamvu ndi yapamwamba.

3. Pulasitiki ili ndi kukana dzimbiri.

4. Pulasitiki imakhala ndi zotsekemera zabwino komanso kutentha kwa kutentha.

Pali mitundu yambiri ya mapulasitiki.Kodi mitundu yayikulu ya thermoplastics ndi iti?

1. Polyvinyl chloride (PVC) ndi imodzi mwamapulasitiki ofunikira kwambiri.Pakati pa mapulasitiki asanu apamwamba kwambiri padziko lonse lapansi, mphamvu yake yopanga ndi yachiwiri kwa polyethylene.PVC ili ndi kuuma kwabwino komanso kukana dzimbiri, koma ilibe kukhazikika, ndipo monomer yake ndi yakupha.

2. Polyolefin (PO), yodziwika kwambiri ndi polyethylene (PE) ndi polypropylene (PP).Pakati pawo, PE ndi imodzi mwazinthu zazikulu kwambiri zamapulasitiki.PP ili ndi kachulukidwe kakang'ono kachibale, sichikhala ndi poizoni, sichinunkhiza komanso chimakhala ndi kutentha kwabwino.Itha kugwiritsidwa ntchito kwa nthawi yayitali pa kutentha pafupifupi 110 digiri Celsius.Zathupulasitiki supuniamapangidwa ndi chakudya kalasi PP.

3. styrene resins, kuphatikizapo polystyrene (PS), acrylonitrile-butadiene-styrene copolymer (ABS) ndi polymethyl methacrylate (PMMA).

4. Polyamide, polycarbonate, polyethylene terephthalate, polyoxymethylene (POM).Pulasitiki yamtunduwu imatha kugwiritsidwa ntchito ngati zinthu zomangika, zomwe zimadziwikanso kuti ukadaulo.

Kupezedwa ndi kugwiritsiridwa ntchito kwa mapulasitiki kwalembedwa m’mbiri yakale, ndipo inali njira yachiŵiri yotulukira yofunika imene yakhudza anthu m’zaka za zana la 20.Pulasitiki ndi chozizwitsa padziko lapansi!Masiku ano, tikhoza kunena mosakokomeza kuti: "Moyo wathu sungathe kulekanitsidwa ndi pulasitiki"!