CAJ | 학술논문

用正电子湮没谱研究了两类分别由聚己二酸丁二醇酯多元醇和聚ε-己内酯多元醇合成的线型聚酯型聚氨酯（PBU和PCU）在140～360K温度范围内的结构转变和自由体积特性.研究结果表明，两类聚氨酯(PU)在140～360K温度范围内，都存在三个转变点，其中较低温度的转变(约200K)对应于PU中软段的玻璃化转变温度(Tg)，275K处的转变可能与样品吸附少量水分有关，较高温度的转变（约310K），对于PBU而言对应于软段结晶的熔点，而对于PCU则与在无序的硬段中混入一定量的软段后形成的相容区的Tg有关.当温度低于PU软段的Tg时，两类PU的自由体积尺寸和浓度都随温度升高而增大.当温度高于软段的Tg但低于275K时，自由体积尺寸较快地增加，而自由体积浓度保持不变.温度高于275K并低于软段的熔点或硬段/软段相容区的Tg时,自由体积尺寸增加速度最快，自由体积浓度却保持同样的数值.当温度进一步升高时，自由体积尺寸和浓度都随温度增大而增加.最后研究了这两类PU的自由体积分布与温度的关系.所有这些实验现象均与大分子链的运动有关,并与通过DSC和WAXD表征的材料的形态一致.
용정전자인몰보연구료량류분별유취기이산정이순지다원순화취ε-기내지다원순합성적선형취지형취안지（PBU화PCU）재140～360K온도범위내적결구전변화자유체적특성.연구결과표명，량류취안지(PU)재140～360K온도범위내，도존재삼개전변점，기중교저온도적전변(약200K)대응우PU중연단적파리화전변온도(Tg)，275K처적전변가능여양품흡부소량수분유관，교고온도적전변（약310K），대우PBU이언대응우연단결정적용점，이대우PCU칙여재무서적경단중혼입일정량적연단후형성적상용구적Tg유관.당온도저우PU연단적Tg시，량류PU적자유체적척촌화농도도수온도승고이증대.당온도고우연단적Tg단저우275K시，자유체적척촌교쾌지증가，이자유체적농도보지불변.온도고우275K병저우연단적용점혹경단/연단상용구적Tg시,자유체적척촌증가속도최쾌，자유체적농도각보지동양적수치.당온도진일보승고시，자유체적척촌화농도도수온도증대이증가.최후연구료저량류PU적자유체적분포여온도적관계.소유저사실험현상균여대분자련적운동유관,병여통과DSC화WAXD표정적재료적형태일치.
The structural transitions and free volume properties for two kinds of linear polyurethane prepared with polybutalene adipate polyol and polycaprolactone polyol (PBU and PCU) respectively were studied by means of positron annihilation spectroscopy in the temperature range from 140K to 360K,DSC and WAXD measurements.The experimental results indicated that there were three structural transition temperatures for these two polyurethanes(PUs) from 140K to 360K.The transition at low temperature (at around 200K) was attributed to the glass transition temperature (Tg) of polyester soft segments existing in PU and the transition at 275K could be related to the small amount water adsorbed in PU samples.The high temperature transition (at about 310K) corresponded to the melting point of soft segment crystals in PBU and was also related to the Tg for compatible regions of the disordered hard segments with some soft segments existed in PCU.When the temperature was lower than the Tg of soft segments in PU,both the size and the relative concentration of free volume increased with increasing temperature for PBU and PCU.While the temperature was higher than the Tg of soft segmensts but lower than 275K,the relative concentration of free volume reached a constant value but the size of free volume increased further.When the temperature was higher than 275K but lower than the melting point of soft segment crystals or the Tg of hard/soft segment miscible regions,the relative concentration of free volume still kept constant but the size of free volume increased appreciably.When the temperature increased more,both the size and the relative concentration of free volume existing in PUs increased again.The distributions of free volume were also examined at various temperatures for these two PUs.All these experimental results could be related to the movement of macromolecular chains and the morphologies for these PUs measured by using DSC and WAXD.