인문학
사회과학
자연과학
공학
의약학
농수해양학
예술체육학
복합학
개인구독
소속 기관이 없으신 경우, 개인 정기구독을 하시면 저렴하게
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지원사업
학술연구/단체지원/교육 등 연구자 활동을 지속하도록 DBpia가 지원하고 있어요.
커뮤니티
연구자들이 자신의 연구와 전문성을 널리 알리고, 새로운 협력의 기회를 만들 수 있는 네트워킹 공간이에요.
초록·키워드
The gelation behavior of poly(vinyl alcohol) (PVA) solutions in dimethyl sulfoxide (DMSO) containing boric acid (BA, $H_3BO_3$) under shear stress was rheologically investigated in terms of temperature and molecular weight of PVA. Time-dependent rheological properties of the solutions were analyzed to determine the effects of stress on the gelation mechanism. The solutions of low weight-average molecular weight ($M_w=31,000-50,000$) PVA showed more noticeable temperature-dependent viscosity changes than those of high weight-average molecular weight ($M_w=165,000-186,000$) PVA. The viscosity increase caused by stress indicated that the formation of the gel structure was promoted by stress. In time sweep experiments, all the PVA solutions showed stress-dependent rheological responses except for the high $M_w$ PVA solutions at $30^{\circ}C$. The viscosities of the solutions remained constant over the observed shearing time, indicating the formation of an irreversible gel. The effects of stress history were reconfirmed by the results of frequency sweep experiments. Antecedent shearing gave rise to many different time-dependent rheological responses. At $60^{\circ}C$, both low and high $M_w$ PVA solutions had loss tangent values (tan ${\delta}$) less than 1. Furthermore, the formation of gel structures increased the relaxation time (${\lambda}$) by up to 10 s.
본문·목차
인공지능 문자 인식 모델을 통해 추출된 텍스트로, 일부 오타나 오류가 포함될 수 있으나 지속적으로 개선 중입니다.
오류를 발견하셨다면 해당 부분을 드래그한 후 ' 를 통해 신고해주세요.
오류를 발견하셨다면 해당 부분을 드래그한 후 ' 를 통해 신고해주세요.