1、1,Chapter 2. Shape Memory Polymers,http:/ Contents of This Chaper,Introduction of SMPs Main type of SMPs Main kinds of SMPs systems Research directions of SMPs,3,2.1 Introduction of SMPs,是一类新型的功能高分子材料，当外部条件发生变化时，它可相应地改变开关并将其固定（变形态）；如果外界环境以特定的方式和规律再次发生变化，它们便可逆的恢复至起始态。,2.1.1 Definition- Shape memory p
2、olymers, SMPs,4,Figure 1. shape memory effect of flowers (opening),Original shape: open flower,Second shape: closed flower,Responsive to temperature,Manufactured by external force,例1：,5,Shape-memory polymers (SMPs) are polymeric smart materials that have the ability to return from a deformed state (
3、temporary shape) to their original (permanent) shape induced by an external stimulus (trigger), such as temperature change,SMPs can retain two or sometimes three shapes, and the transition between those is induced by temperature. In addition to temperature change, the shape change of SMPs can also b
4、e triggered by an electric or magnetic field, light or solution.,6,2.1.2 Classification of SMP,Temperature change,Heat induced by, resulting in temperature change,Light-induced chromophores,surrouding medium changing Like pH value， Ionic etc.,7,2.1.3 Comparison between SMP and SMA,8,A summary of the
5、 major differences between SMPs and SMAs,9,2.1.4 Structure of SMPs：,hard phase,Soft phase,Micro-phase separation structure composed of two phase:,10,Deform,Fix,Recover,cool,heat,: switch unit/segment,: Netpoint /domain,Ttrans,Ttrans,cool,Above Ttrans,Below Ttrans,2.1.5 Mechanism of shape memory effe
6、ct of SMPs,11,2.1.6 Shape memory behavior/ process,Deformation 形变,temperature,Tg,Tm,Tf,http:/ Character of SMPs and its principle,形状记忆聚合物制备条件： 1）聚合物本身应有结晶和无定形的两相结构，且两相结构的比例适当； 2）在玻璃化温度或熔点以上的较宽温度范围内呈现高弹态，并具有一定强度， 以利于变形； 3）在较宽的环境温度条件下具有玻璃态，保证在贮存状态下冻结应力不会释放。,13,Requirements for polymer having shape mem
7、ory effects ： 1）Polymers have two phase: soft phase and hard phase, which can be either amorphous phase or semi-crystalline phase; and their phase percentage are suitable； 2 Polymer is elastic with a certain strength within the temperature range above Tg or Tm；(for deformation) 3）There is another wi
8、de temperature range below Tg or Tm, In which the polymer is amorphous or semi-crystalline , (for fixing temporary shape and storing the inner stress,14,2.1.8 Available Forms of SMPs, 可以制作的不同形式的形状记忆材料,15,2.2 Main type of SMPs,Thermal-induced SMPs Light-induced SMPs Chemistry sensitive SMPs,16,Therma
9、l-induced SMPs,两相结构： 固定相： 防止树脂流动并记忆超始态。物理交联结构-热塑性SMP化学交联结构-热固性SMP 2. 可逆相：随温度变化能可逆地固化和软化。物理交联结构：结晶态，玻璃态,Mechanism of thermal-induced SMEs,17,Two important quantities that are used to describe shape-memory effects are the strain recovery rate (Rr) and strain fixity rate (Rf). The strain recovery rate
10、describes the ability of the material to memorize its permanent shape, while the strain fixity rate describes the ability of switching segments to fix the mechanical deformation.,Characterization of SMPs,18,Shape memory effects 1. Parameters of shape memory effectshape fixity rate 形状固定率- 90-100%shap
11、e recovery rate 形状恢复率- 90-100%shape recovery temperature 形状恢复温度- 30-70shape recovery force 形状恢复力- 9.21-29.4MPashape recovery speed 形状恢复速度-2. Direction of shape memory effect 形状记忆的方向性One-way shape memory effect 单向记忆Two-way shape memory effect 双向记忆All-round shape memory effect,19,Light-induced SMPs,UV
12、260nm,去除外力,20,Light-activated shape-memory polymers (LASMP) use processes of photo-crosslinking and photo-cleaving to change Tg. Photo-crosslinking is achieved by using one wavelength of light, while a second wavelength of light reversibly cleaves the photo-crosslinked bonds. The effect achieved is
13、that the material may be reversibly switched between an elastomer and a rigid polymer. Light does not change the temperature, only the cross-linking density within the material. For example, it has been reported that polymers containing cinnamic groups can be fixed into predetermined shapes by UV li
14、ght illumination ( 260 nm) and then recover their original shape when exposed to UV light of a different wavelength ( 260 nm). Examples of photoresponsive switches include cinnamic acid and cinnamylidene acetic acid.,21,Light-induced SME 光致形状记忆效应,1. Deformation 2% (up to 200% in gel） 2. have light-i
15、nduced heating 光致热效应。,22,Chemistry sensitive SMPs,L,L+ L”,化学物质,For example： pH value changing， （in polymer electrolyte ） Exchange of ionic平衡离子置换，（羧酸阴离子的平衡离子置换） Chelating reaction 螯合反应， e.g. PVA与Cu2+ phase transition 相转变 e.g. 蛋白质在各种盐类物质下oxidation-reduction reaction, redox reaction 氧化还原反应,10%-300% 形变量
16、,23,others,Electro-active SMPs Magnetically induced SMPs water-driven SMPs pH sensitive SMPs Moisture-sensitive SMPs ,24,2.3 SMP types and applications,2.3.1 shape memory polymer systems 2.3.1.1 Trans-polyisoprene-based SMPs 反式聚异戊二烯 (TPI)1988年，日本可乐丽公司开发。是TPI树脂，填料及交联剂等原料经科学配方，用双辊混练机或密练机，以及挤出机等混练制成。 形
17、状记忆回复温度由TPI熔点所决定。 优点：形变量大，加工成型容易，形状回复可调整，耐溶剂性好，耐酸碱，高度的绝缘性，极好的耐寒性及耐臭氧性等。,25,反式聚异戊二烯,天然橡胶,26,苯乙烯-丁二烯共聚物 （Styrene-butadiene copolymer),1988年 日本旭化成工业公司推出 ，商品名：阿斯玛 固定相：聚苯乙烯 可逆相：聚丁二烯结晶区域 特点：不仅形变量大（可达400%），且形状恢复速度快，常温保存时，形状的自然恢复极少，重复形变时，恢复率有所下降，至少可使用200次以上。另外，耐酸碱性好，着色性优良。,27,polystyrene,Styrene-butadiene-S
18、tyreneSBS,28,聚降冰片烯（Polynorbornene),1974年，法国诺索洛公司（法国煤化学公司 dF Chimie) 分子量高达300万，Tg 为35度 固定相（fixing phase)：为超高分子链的缠绕交联， 可逆相( reversible phase)：玻璃态转变结构。四大特点： 1）热塑性树脂，可成型加工，但分子量太高，加工较为困难。 2）Tg接近人体温度，室温下为硬质，适于制作人体织物，但温度不便于任意调整。 3）充油处理后变成JIS硬度为15的低硬度橡胶，具有较好的耐湿气性和滑动性。 4）未经硫化的试样强度高，具有减震性能。,29,30,聚氨酯（Polyuret
19、hane),1988年日本三菱重工业公司 可逆相：软段的聚酯部分 固定相：硬段聚集成的微区起物理交联点作用 优点： 1）加工性好。 2）形变回复量大； 3）在-30-70 oC之间自由选择形状回复温度； 4）树脂材料透明，可任意着色。 5）相对密度1.1-1.2，较SMA低。 6）成本低，,31,32,鞋底,密封圈,油漆,滑轮,33,34,其他种类,聚酯 （polyester) 交联聚乙烯(cross-linked Polyethylene ) 环氧树脂，乙烯-酯酸乙烯共聚物，聚氯乙烯，聚偏氟乙烯，聚四氟乙烯，聚己内酯，聚酰胺等,35,SMPs的不足之处： 与通用塑料相比，价格较高 形状回复精
20、度低； 力学强度和化学耐久性，耐油性，耐热性，耐药品性等性能不够理想； 形状记忆功能只有单向的，没有双向性记忆和全方位记忆性能 形状记忆树脂的加工性要比原树脂差。,36,2.3.2 Applications of SMPs 形状记忆高分子的应用,2.3.2.1. 热收缩套管：交联聚乙烯 2.3.2.2. 容器外包及衬里 2.3.2.3. 包装材料 2.3.2.4. 建筑用紧固销钉 2.3.2.5. 医用器材 2.3.2.6 纺织面料 2.3.2.7. 其他,37,38,Great potential application in medical field,39,瑞迪艾申放疗固定膜采用100的
21、形状记忆低温热塑材料,40,41,42,管道连接,43,不久的将来，汽车的外壳也可以用记忆合金制作。如果不小心碰瘪了，只要用电吹风加加温就可恢复原状，既省钱又省力，实在方便。,44,45,46,2.4 Future directions of SMPs,2.4.1.Biodegradable SMPs,47,Liquid crystalline elastomer SMP,48,By Min-hui Li etal, Advanced materials,2004.16(21):1922-1925,49,Supramolecular SMPs,50,参考文献,作者: 朱光明 形状记忆聚合物及其
22、应用 ISBN: 9787502540654, 7502540652,Behl M and Lendlein A,Shape-memory polymers,Materials Today 2007;10:20-28 Liu C, Qin H and Mather PT, Review of progress in shape-memory polymers, Journal of Materials Chemistry 2007;17:1543-1558. Ratna D and Karger-Kocsis J,Recent advances in shape memory polymers and composites: a review,Journal of Materials Science 2008;43:254-269,51,52,Thank you!,
