Article
  • Swelling and Mechanical Properties of Thermo-and pH-sensitive Interpenetrating Polymer Networks Based on Poly(N-isopropylacrylamide)
  • Pyun DK, Lim YH, An JH, Kim D, Lee DS
  • Poly(N-isopropylacrylamide)를 기초로 한 온도/pH 민감성 상호침투 고분자의 팽윤 및 기계적 특성
  • 편도기, 임영호, 안정호, 김덕준, 이두성
Abstract
Interpenetratlng polymer networks (IPNS) composed of polyurethane (PU) and poly(N-isopropylacryamide) (P(NiPAAm) ) were synthesized. The swelling behavior in water was examined as a function of temperature. The equilibrium swelling ratio decreased with increasing hydrophobic PU content, but the gel collapse point was not significantly affected by the incorporated PU content. Differential scanning calorimetry thermograms of the swollen IPNs exhibited the same swelling transition temperature as that of P(NiPAAm), although the degree of swelling was affected by IPN composition. These observations indicate that each network in the swollen IPNS exists independently. The aqueous swelling-deswelling kinetics of IPNs by temperature modulation could be controlled by gel composition and temperatures applied. For the preparation of thermosensitive hydrogels with an adjustable thermosensitivity, poly(N-isopropylacrylamide)/poly(acrylic acid) (P(AAc)) IPNS were synthesized with various NiPAAm to AAc ratios. For the IPN haying a low AAc to NiPAAm ratio, a negative thermosensitivity (a decreasing swelling ratio with increasing temperature) was found, with pH affecting the degree of thermosensitivity. The effect of pH on the thermosensitivity was due to the charge in the P(AAc) network. At high temperatures, IPN collapsed at, pH 3, but remained swollen at pH 7. P(NiPAAm)/P(AAc) SIPNs synthesized using different solvents having similar solubility parameters illustrated similar swelling behavior one another. No pH effect on the transition temperature was observed.

Poly(N-isopropylacrylamide(P(NiPAAm))/polyurethane (PU)와 poly(N-isopropyl-acrylamide)/poly(acrylic acid) (PAAc) interpenetrating polymer networks (IPNs)의 온도 변화에 따른 수팽윤거동을 관찰하였다. P(NiPAAm)/PU IPN의 경우 소수성 PU의 함량이 증가할수록 수팽윤비는 감소하였으나 겔의 붕괴온도에는 별다른 영향을 주지 않았다. 이러한 결과는 DSC에 의하여 확인되었으며 이는 팽윤된 IPN계에서 각 망상구조가 독립적인 거동을 보인다는 것을 의미한다. 온도 조율에 의한 팽윤-수축 kinetics는 겔의 조성과 적용된 온도에 따라 결정되었다. P(NiPAAm)/PU치 기계적 성질을 응력-변형 거동에 따른 탄성률로 부터 파악한 결과 일정한 수팽윤정도에 대하여 PU의 조성이 증가함에 따라 탄성률이 증가 하였다. P(NiPAAm)/P(AAc)IPNs의 팽윤거동에 있어서는 저농도의 AAc를 함유한 IPN은 온도가 상승함에 따라 수괭윤비가 저하되는 음의 열민감성을 나타내었으며 pH는 이러한 열민감도에 커다란 영향을 주었다. 온도감응정도에 대한 pH의 영향은 P(AAc)에 존재하는 전하에 기인하는 것으로 pH가 3에서는 IPN이 수축되었으나 pH가 7에서는 일정한 팽윤상태를 지속하였다. 용해도상수가 비숫한 몇가지 다른 용매를 사용하여 중합된 P(NiPAAm)/P(AAc) IPNS의 팽윤거동은 서로 비슷하게 나타났다. 팽윤전이온도에 대한 pH의 영향은 무시할 수 있었다.

Keywords: IPN; hydrogel; swelling; thermosensitivity; pH sensitivity

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  • Polymer(Korea) 폴리머
  • Frequency : Bimonthly(odd)
    ISSN 0379-153X(Print)
    ISSN 2234-8077(Online)
    Abbr. Polym. Korea
  • 2023 Impact Factor : 0.4
  • Indexed in SCIE

This Article

  • 1996; 20(2): 335-346

    Published online Mar 25, 1996