{"id":5076,"date":"2022-02-21T07:36:59","date_gmt":"2022-02-21T07:36:59","guid":{"rendered":"https:\/\/longchangchemical.com\/?p=5076"},"modified":"2026-04-28T10:41:56","modified_gmt":"2026-04-28T10:41:56","slug":"analysis-of-factors-affecting-molecular-weight-of-polybutyl-acrylate-leveling-agent","status":"publish","type":"post","link":"https:\/\/longchangchemical.com\/tr\/analysis-of-factors-affecting-molecular-weight-of-polybutyl-acrylate-leveling-agent\/","title":{"rendered":"Polib\u00fctil Akrilat Tesviye Maddesinin Molek\u00fcl A\u011f\u0131rl\u0131\u011f\u0131n\u0131 Etkileyen Fakt\u00f6rlerin Analizi"},"content":{"rendered":"

Polib\u00fctil Akrilat Tesviye Maddesinin Molek\u00fcl A\u011f\u0131rl\u0131\u011f\u0131n\u0131 Etkileyen Fakt\u00f6rlerin Analizi<\/strong><\/h1>\n

<\/p>\n

Quick answer:<\/strong> For UV monomer and resin selection, the key commercial question is not \u201cwhich material is best in general\u201d but \u201cwhich package delivers the right balance of flow, cure, adhesion, and durability in the real application.\u201d<\/p>\n

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1. Giri\u015f: Tesviye maddesinin rol\u00fc: Toz kaplama eritildi\u011finde ve tesviye edildi\u011finde, \"s\u0131v\u0131 faz\" ve \"s\u0131v\u0131-kat\u0131 faz\" olmak \u00fczere iki aray\u00fczey vard\u0131r. Tesviye maddesinin ana molek\u00fcler zinciri, eriyik y\u00fczeyinde \u00e7ok ince bir monomolek\u00fcler tabaka olu\u015fturabilir, bu da \"s\u0131v\u0131 fazda\" d\u00fczg\u00fcn bir y\u00fczey gerilimi sa\u011flar ve i\u011fne delikleri ve b\u00fcz\u00fclme delikleri gibi boya hastal\u0131klar\u0131n\u0131n ortadan kald\u0131r\u0131lmas\u0131na yard\u0131mc\u0131 olur; ayn\u0131 zamanda, tesviye maddesinin yan Zincir ester grubu, eriyik kaplaman\u0131n y\u00fczey gerilimini kontroll\u00fc bir \u015fekilde azaltabilir, bu da kaplama ile kaplanm\u0131\u015f i\u015f par\u00e7as\u0131n\u0131n \"s\u0131v\u0131-kat\u0131 faz\u0131n\u0131n\" y\u00fczeyi aras\u0131ndaki \u0131slanma ve yap\u0131\u015fma i\u00e7in yard\u0131mc\u0131 olur ve ayn\u0131 zamanda alt tabakan\u0131n iyi \u0131slanmas\u0131n\u0131 ve yay\u0131lmas\u0131n\u0131 sa\u011flar.<\/p>\n

Polibutilakrilat, toz boyalar i\u00e7in en yayg\u0131n kullan\u0131lan d\u00fc\u015f\u00fck maliyetli malzemelerden biridir. G\u00fc\u00e7l\u00fc y\u00fczey aktivitesi g\u00f6sterir, bunun ana nedeni re\u00e7ine-fobik \u00f6zelliklere sahip nispeten temiz bir \"-C-C-\" ana zincirine sahip olmas\u0131 ve yan zincirin re\u00e7ine dostu \u00f6zelliklere sahip \"butil ester grubu\" olmas\u0131d\u0131r; b\u00f6yle bir yap\u0131, aray\u00fczeyde Serbest oryantasyon sa\u011flar, ester ba\u011f\u0131n\u0131n s\u0131v\u0131 faz ile uyumlu k\u0131sm\u0131 i\u00e7e do\u011frudur, ana zincir d\u00fczg\u00fcn bir tek tabaka olu\u015fturmak i\u00e7in aray\u00fczey \u00fczerinde y\u00fczer ve y\u00fczey gerilimi tekd\u00fcze olabilir. Polimerizasyon derecesi \"n\" molek\u00fcler a\u011f\u0131rl\u0131\u011f\u0131n boyutunu yans\u0131t\u0131r.<\/p>\n

2. S\u0131v\u0131 ak\u0131\u015f\u0131n\u0131n en makul molek\u00fcler a\u011f\u0131rl\u0131\u011f\u0131 nedir?<\/p>\n

Yerli ve yabanc\u0131 uzmanlar\u0131n raporlar\u0131na g\u00f6re, y\u00fczey gerilimi, ana zincirin esnekli\u011fi, alt tabakan\u0131n \u0131slanabilirli\u011fi, pigment dolgu maddesinin \u0131slanabilirli\u011fi ve kaps\u00fcllenmesi, molek\u00fcllerin hareketlili\u011fi ve sentez s\u00fcrecinin i\u015flerli\u011fi, olu\u015fumu Kaplaman\u0131n parlakl\u0131\u011f\u0131, dolgunlu\u011fu ve belirginli\u011fi perspektiflerinden, sonu\u00e7lar genellikle a\u015fa\u011f\u0131daki g\u00f6stergelere e\u011filimlidir: Mn=4000-5000; Mw=7000-10000, molek\u00fcler a\u011f\u0131rl\u0131k da\u011f\u0131l\u0131m\u0131 polidispersite Mw\/Mn=1.5-2.2, Bu polib\u00fctil akrilat\u0131n en ideal molek\u00fcler yap\u0131 indeksidir.<\/p>\n

20.000'in \u00fczerindeki molek\u00fcllerin sistemle uyumlu olmas\u0131 zordur \u00e7\u00fcnk\u00fc molek\u00fcller \u00e7ok b\u00fcy\u00fckt\u00fcr ve \u0131\u015f\u0131k kaybetme veya s\u00f6nme e\u011filimindedir; 4.000'in alt\u0131nda ve 20.000'in \u00fczerinde ak\u0131\u015f molek\u00fclleri, oran ne kadar az olursa o kadar iyidir. Vurgulanmaya de\u011fer bir nokta: Mn=3000-10000, molek\u00fcler a\u011f\u0131rl\u0131k da\u011f\u0131l\u0131m\u0131 Mw\/Mn=1.5-7.0 da mevcuttur; ancak bazen \u015fu gibi sorunlar olacakt\u0131r: \u00e7ok fazla k\u00fc\u00e7\u00fck molek\u00fcl ve s\u00fcper molek\u00fcl i\u00e7eri\u011fi, i\u011fne delikleri ve \u0131\u015f\u0131k kayb\u0131 g\u00f6r\u00fcnecektir, anti-parazit vb. 4000'in alt\u0131ndaki molek\u00fcller, molek\u00fcller \u00e7ok k\u00fc\u00e7\u00fck oldu\u011fundan ve uyumluluk \u00e7ok iyi oldu\u011fundan, bu tesviye \u00f6zelli\u011fini kaybedecek ve \u0131\u015f\u0131\u011fa bakarken t\u00fcm k\u00fc\u00e7\u00fck dalgalanmalara neden olacakt\u0131r; a\u015fa\u011f\u0131da g\u00f6sterildi\u011fi gibi:<\/p>\n

3. Sentetik malzemeler: Molek\u00fcler a\u011f\u0131rl\u0131k aral\u0131\u011f\u0131 belirlendikten sonra, geriye kalan i\u015f hammadde bulmak ve bu hedef etraf\u0131nda s\u00fcreci belirlemektir. Ana malzemeler \u015funlard\u0131r: n-butil akrilat, ksilen \u00e7\u00f6z\u00fcc\u00fc, azo AIBN kataliz\u00f6r\u00fc, molek\u00fcler a\u011f\u0131rl\u0131k d\u00fczenleyici. Maliyetleri d\u00fc\u015f\u00fcrmek i\u00e7in kopolimerizasyon i\u00e7in 3%-5% stiren eklenebilir; baz\u0131 \u015firketler ayr\u0131ca vinil trimetikon, hidroksietil akrilat, oktil akrilat veya izooktil akrilat ile modifiye edilmi\u015f 2-etilheksil akrilat kullan\u0131r. Esas olarak s\u0131k\u0131\u015fma \u00f6nleme performans\u0131n\u0131 art\u0131rmak i\u00e7in y\u00fczey gerilimini azaltmak i\u00e7in bunlar faydal\u0131 yeniliklerdir. Maliyetleri d\u00fc\u015f\u00fcrmek i\u00e7in, baz\u0131 fabrikalar do\u011frudan dioktil tereftalat, izooktil tereftalat, dietil fumarat, dietil maleat, epoksi Soya fasulyesi ya\u011f\u0131 vb. ekler, genel dozaj yakla\u015f\u0131k 20%'dir. Bu uygulamalar tesviye ve anti-parazit i\u00e7in elveri\u015fli de\u011fildir.<\/p>\n

\u00c7\u00f6z\u00fcc\u00fc se\u00e7imi \u00e7e\u015fitlilik g\u00f6stermektedir. \u0130lk a\u015famada toluen (kaynama noktas\u0131 110.63 \u00b0C) kullan\u0131lm\u0131\u015f, ancak toksisite ve d\u00fc\u015f\u00fck kaynama noktas\u0131 sorunlar\u0131 nedeniyle yava\u015f yava\u015f ksilen (138.5~141.5 \u00b0C) kullan\u0131lm\u0131\u015ft\u0131r. Etilen glikol monometil eter (veya etilen glikol monometil eter) de \u00e7ok ideal bir \u00e7\u00f6z\u00fcc\u00fcd\u00fcr. Toksisitesi ksilene g\u00f6re daha d\u00fc\u015f\u00fckt\u00fcr ve kaynama noktas\u0131 124,6 \u00b0C'dir. \u00c7in'de yayg\u0131n olarak kullan\u0131lmamaktad\u0131r ve yurtd\u0131\u015f\u0131nda \u00e7\u00f6z\u00fcc\u00fc olarak ksilen ile kar\u0131\u015ft\u0131rma y\u00f6ntemi \u00e7ok de\u011ferlidir. Kaynama noktas\u0131 \u00e7ok d\u00fc\u015f\u00fckse, sentetik tesviye maddesinin molek\u00fcler a\u011f\u0131rl\u0131\u011f\u0131 \u00e7ok b\u00fcy\u00fckt\u00fcr, bu da k\u00f6p\u00fck giderme e\u011filimindedir, ancak kapasite \u0131\u015f\u0131k kaybeder ve bu\u011fulan\u0131r. Y\u00fcksek kaynama noktas\u0131na sahip solventler kullan\u0131m i\u00e7in uygun de\u011fildir \u00e7\u00fcnk\u00fc solvent buharla\u015fma s\u0131cakl\u0131\u011f\u0131 \u00e7ok y\u00fcksektir, bu da bitmi\u015f \u00fcr\u00fcn\u00fc sararmaya ve makromolek\u00fcller olu\u015fturmaya oksitlemek kolayd\u0131r. \u015eu anda \u00c7in'deki ana ak\u0131m, \u00e7\u00f6z\u00fcc\u00fc olarak kar\u0131\u015f\u0131k ksilen kullanmakt\u0131r. Hammaddeler uygun fiyatl\u0131, ucuz, toksisitesi d\u00fc\u015f\u00fck, depolanmas\u0131 kolay, kullan\u0131m\u0131 kolay ve g\u00fcvenlidir.<\/p>\n

Ba\u015flat\u0131c\u0131 olarak neden dibenzoil peroksit BPO yerine azobizob\u00fctironitril AIBN kullan\u0131l\u0131yor? Temel olarak iki fakt\u00f6r g\u00f6z \u00f6n\u00fcnde bulundurulur: Birincisi, ba\u015flat\u0131c\u0131n\u0131n t\u00fcr\u00fc ve miktar\u0131 polimerin ba\u011f\u0131l molek\u00fcler a\u011f\u0131rl\u0131\u011f\u0131n\u0131 ve molek\u00fcler yap\u0131s\u0131n\u0131 etkileyebilir ve b\u00f6ylece re\u00e7inenin kimyasal ve fiziksel \u00f6zelliklerini etkileyebilir. Azobisisobutironitril (AIBN ) ve dibenzoil peroksit (BPO) s\u0131ras\u0131yla farkl\u0131 bozunma kineti\u011fine sahiptir. AIBN'nin zincir transfer sabiti k\u00fc\u00e7\u00fckt\u00fcr, ayr\u0131\u015fma h\u0131z\u0131 farkl\u0131 \u00e7\u00f6z\u00fcc\u00fclerde \u00e7ok farkl\u0131 de\u011fildir, serbest radikallerin aktivitesi benzen radikallerinden daha azd\u0131r, zincir transfer reaksiyonu daha azd\u0131r ve elde edilen polimer daha dar bir ba\u011f\u0131l molek\u00fcler k\u00fctle da\u011f\u0131l\u0131m\u0131na sahiptir. Ba\u015flat\u0131c\u0131 olarak AIBN kullan\u0131l\u0131r. Bu ajan re\u00e7ine viskozitesini daha uygun bir aral\u0131kta tutabilir. Bununla birlikte, BPO ayr\u0131\u015ft\u0131r\u0131ld\u0131ktan sonra, daha y\u00fcksek aktiviteye sahip benzen radikalleri \u00fcretmek kolayd\u0131r ve benzen radikallerinin polimer \u00fczerindeki hidrojen atomlar\u0131n\u0131 yakalamas\u0131 kolayd\u0131r. monomer<\/strong><\/a><\/span> veya polimer molek\u00fcler zinciri, dallanma ve \u00e7apraz ba\u011flanma ile sonu\u00e7lan\u0131r, ba\u011f\u0131l molek\u00fcler k\u00fctle da\u011f\u0131l\u0131m\u0131n\u0131 geni\u015fletir ve polimerin viskozitesini azalt\u0131r. \u00f6nemli \u00f6l\u00e7\u00fcde artm\u0131\u015ft\u0131r. \u0130kincisi: azo AIBN taraf\u0131ndan ba\u015flat\u0131lan polimerizasyon taraf\u0131ndan olu\u015fturulan u\u00e7 grup, daha iyi d\u0131\u015f mekan dayan\u0131kl\u0131l\u0131\u011f\u0131na sahip olan (CH3)3C-'dir; BPO taraf\u0131ndan ba\u015flat\u0131lan polimer taraf\u0131ndan olu\u015fturulan u\u00e7 grup ise, d\u0131\u015f hava ko\u015fullar\u0131na kar\u015f\u0131 zay\u0131f bir dirence sahip olan ve uzun bir s\u00fcre sonra kaplama filmine yol a\u00e7acak olan bir benzen halkas\u0131d\u0131r. Sararma ve ya\u015flanma. Genel olarak, ba\u015flat\u0131c\u0131n\u0131n k\u00fctle oran\u0131 4%'den b\u00fcy\u00fck oldu\u011funda, polimerin mekanik \u00f6zelliklerinin, kimyasal \u00f6zelliklerinin ve termal stabilitesinin olumsuz etkilenece\u011fine inan\u0131lmaktad\u0131r.<\/p>\n

Uygulama, polib\u00fctil akrilat tesviye maddesinin sentezlenmesi s\u00fcrecinde a\u015fa\u011f\u0131daki \u00f6nemli noktalar\u0131n iyi kontrol edilmesi gerekti\u011fini kan\u0131tlam\u0131\u015ft\u0131r:<\/p>\n

1) Toplam bor\u00e7 tutar\u0131n\u0131n monomer<\/strong><\/a><\/span> \u00e7\u00f6z\u00fcc\u00fcye oran\u0131 \u2248 1: (1.0-1.2): Bu oran, molek\u00fcler a\u011f\u0131rl\u0131\u011f\u0131n polidispersitesi \u00fczerinde b\u00fcy\u00fck bir etkiye sahiptir. T\u00fcm reaksiyon s\u00fcreci bir \"a\u00e7l\u0131k\" reaksiyonu olmas\u0131na ra\u011fmen, \u00e7\u00f6z\u00fcc\u00fc fazla durumdad\u0131r, ancak \u00e7\u00f6z\u00fcc\u00fcdeki her bir bile\u015fenin konsantrasyonu, \u00e7\u00f6z\u00fcc\u00fc miktar\u0131ndaki art\u0131\u015f nedeniyle b\u00fcy\u00fck \u00f6l\u00e7\u00fcde de\u011fi\u015fir. monomer<\/a><\/strong><\/span> damlama ve reaktanlar\u0131n olu\u015fumu. Y\u00fczey gerilimi kaplaman\u0131n d\u00fczle\u015fmesini ve dolgunlu\u011funu olumsuz etkiler.
\n2) Damlama h\u0131z\u0131: D\u00fczg\u00fcn ve kademeli damla damla ekleme avantajl\u0131d\u0131r. Kimyasal reaksiyon bir anda ger\u00e7ekle\u015ftirilir. Reaksiyon ko\u015fullar\u0131na ula\u015f\u0131ld\u0131\u011f\u0131nda, reaksiyon saniyenin on binde biri i\u00e7inde tamamlanabilir. \u00d6zellikle aceleci davranmamak ve rahat olmak \u00e7ok \u00f6nemlidir. Molek\u00fcler a\u011f\u0131rl\u0131\u011f\u0131n polidispersitesi bundan b\u00fcy\u00fck \u00f6l\u00e7\u00fcde etkilenir.
\n3) \u0130\u00e7indeki su i\u00e7eri\u011finin etkisi monomerler<\/strong><\/span><\/a> ve \u00e7\u00f6z\u00fcc\u00fcler: hem monomerler hem de \u00e7\u00f6z\u00fcc\u00fcler \u00e7ok fazla olmasa da \u22645\u2030 su i\u00e7erecektir, ancak \u00e7\u00f6z\u00fcc\u00fc geri d\u00f6n\u00fc\u015ft\u00fcr\u00fcld\u00fc\u011f\u00fc i\u00e7in su birikmeye devam edecektir. Az miktarda su, \u00e7\u00f6z\u00fcc\u00fc veya monomer ile reaksiyon kazan\u0131na girer ve \u0131s\u0131t\u0131ld\u0131ktan sonra ksilen ile azeotropla\u015f\u0131r, b\u00fcy\u00fck miktarda azo AIBN t\u00fcketir, maliyeti art\u0131r\u0131r ve daha sonra kullan\u0131ma elveri\u015fli olmayan molek\u00fcler a\u011f\u0131rl\u0131k da\u011f\u0131l\u0131m\u0131n\u0131 etkiler.
\n4) Azo ekleme zamanlamas\u0131 ve oran\u0131: Bu i\u015flemin amac\u0131, reaksiyona girmemi\u015f k\u00fc\u00e7\u00fck molek\u00fcllerin veya monomerlerin reaksiyona girmeye devam etmesini sa\u011flamak, daha sonra \u00e7\u00f6z\u00fcc\u00fc buharla\u015ft\u0131r\u0131ld\u0131\u011f\u0131nda reaksiyona girmemi\u015f k\u00fc\u00e7\u00fck molek\u00fcllerin \u00e7\u00f6z\u00fcc\u00fcye girmesini ve bir sonraki reaksiyonu etkilemesini \u00f6nlemektir. Kazan\u0131n monomer konsantrasyon oran\u0131 ve molek\u00fcler a\u011f\u0131rl\u0131k da\u011f\u0131l\u0131m\u0131. Genel olarak, toplam ba\u015flat\u0131c\u0131 miktar\u0131n\u0131n onda biri kullan\u0131labilir.
\n5) Is\u0131 koruma s\u00fcresi ve solvent buharla\u015fma s\u00fcresinin molek\u00fcler a\u011f\u0131rl\u0131k \u00fczerinde \u00e7ok az etkisi vard\u0131r, ancak s\u0131cakl\u0131k \u00e7ok y\u00fcksek olmamal\u0131 ve s\u00fcre \u00e7ok uzun olmamal\u0131d\u0131r. \u00c7\u00f6z\u00fcc\u00fcn\u00fcn d\u00fc\u015f\u00fck s\u0131cakl\u0131kta vakumla buharla\u015ft\u0131r\u0131lmas\u0131 nihai \u00fcr\u00fcn\u00fcn kromatikli\u011fi i\u00e7in faydal\u0131d\u0131r. S\u0131cakl\u0131k ne kadar d\u00fc\u015f\u00fck ve s\u00fcre ne kadar k\u0131sa olursa, o kadar elveri\u015flidir, tabii ki \u00f6nc\u00fcl, \u00e7\u00f6z\u00fcc\u00fcn\u00fcn tamamen buharla\u015ft\u0131r\u0131lmas\u0131 gerekti\u011fidir.
\n6) \u00dc\u00e7 a\u015famal\u0131 filtreleme: yani, \u00e7\u00f6z\u00fcc\u00fc ve monomer reaksiyon kazan\u0131na ve damlayan depolama tank\u0131na girerken filtrelenmelidir; Filtre eleman\u0131 veya filtre s\u00fczgeci d\u00fczenli olarak temizlenmeli ve de\u011fi\u015ftirilmelidir, bu da jelle\u015fmi\u015f partik\u00fcllerin veya safs\u0131zl\u0131klar\u0131n filtrelenmesine yard\u0131mc\u0131 olur. Bu i\u015flemlerin molek\u00fcler a\u011f\u0131rl\u0131k da\u011f\u0131l\u0131m\u0131 \u00fczerinde \u00e7ok az etkisi olmas\u0131na ra\u011fmen, y\u00fcksek kaliteyi sa\u011flamak i\u00e7in kesinlikle gereklidir.
\n7) Yukar\u0131daki operasyon kontrol\u00fc sayesinde, \u00fcretilen \u00fcr\u00fcnler \u00fczerinde GPC jel kromatografi testi ger\u00e7ekle\u015ftirdik ve molek\u00fcler a\u011f\u0131rl\u0131k verilerini a\u015fa\u011f\u0131daki gibi elde ettik: say\u0131 ortalama molek\u00fcler a\u011f\u0131rl\u0131\u011f\u0131 4457; k\u00fctle ortalama molek\u00fcler a\u011f\u0131rl\u0131\u011f\u0131 7879; molek\u00fcler a\u011f\u0131rl\u0131k da\u011f\u0131l\u0131m\u0131 1.7679; nispeten ideal.<\/p>\n

Sonu\u00e7 Butil akrilat tesviye maddesi, toz boyalar\u0131n en yayg\u0131n kullan\u0131lan \u00e7e\u015fididir. Bu temelde, modifikasyon i\u00e7in di\u011fer monomerler eklenir ve bir\u00e7ok \u00e7e\u015fit t\u00fcretilir. Sentez s\u00fcre\u00e7leri buna benzer. Bunlar aras\u0131nda molek\u00fcl a\u011f\u0131rl\u0131\u011f\u0131 ve da\u011f\u0131l\u0131m\u0131, y\u00fczey geriliminin b\u00fcy\u00fckl\u00fc\u011f\u00fc ile ilgili en kritik fakt\u00f6r\u00fc etkiler. Burada modifikasyonunu ve t\u00fcrevlerini i\u00e7ermiyor ve sadece en temel k\u0131s\u0131mdaki ki\u015fisel g\u00f6r\u00fc\u015f\u00fcm\u00fc ifade ediyorum. Anla\u015fmazl\u0131klar\u0131n ve hatta yanl\u0131\u015fl\u0131klar\u0131n olmas\u0131 ka\u00e7\u0131n\u0131lmazd\u0131r.<\/p>\n

Bu makalenin ifade etmek istedi\u011fi iki bak\u0131\u015f a\u00e7\u0131s\u0131 vard\u0131r: Birincisi, tesviye maddesinin molek\u00fcler a\u011f\u0131rl\u0131\u011f\u0131n\u0131n y\u00fczey gerilimi ve tesviye \u00fczerinde temel bir etkisi vard\u0131r. \u0130kincisi ise: molek\u00fcler a\u011f\u0131rl\u0131\u011f\u0131n boyutunu etkileyen bir\u00e7ok sentetik fakt\u00f6r vard\u0131r. Operasyon detaylar\u0131 ve operasyonun say\u0131salla\u015ft\u0131r\u0131lmas\u0131, kalite g\u00fcvencesinin temel fakt\u00f6rleridir. Bir\u00e7ok verinin konumland\u0131r\u0131lmas\u0131 ba\u015flang\u0131\u00e7ta do\u011fru olmayabilir ve yanl\u0131\u015f uygulama yoluyla d\u00fczeltilebilir olsa da, bu \u00f6\u011felerin mevcut olmas\u0131 gerekir. S\u00fcrekli iyile\u015ftirme, kaliteyi en u\u00e7 noktaya kadar kontrol etmenin tek yoludur!<\/p>\n

<\/p>\n

A practical sourcing and formulation view of UV monomers and oligomers<\/h2>\n

Most successful UV formulations are built by choosing the backbone first and then tuning the reactive monomer package around the substrate, cure method, and end-use stress. That usually produces a more stable result than choosing materials by viscosity or price alone.<\/p>\n