形狀記憶聚閤物及其多功能復閤材料(導讀版) [Shape-Memory Polymers and Multifunctional Composites]

形狀記憶聚閤物及其多功能復閤材料(導讀版) [Shape-Memory Polymers and Multifunctional Composites] pdf epub mobi txt 电子书 下载 2025

冷勁鬆,杜善義 著,冷勁鬆,杜善義 編
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出版社: 科学出版社
ISBN:9787030327444
版次:1
商品编码:10944507
包装:精装
外文名称:Shape-Memory Polymers and Multifunctional Composites
开本:16开
出版时间:2012-01-01
用纸:胶版纸
页数:373
正文语种:英文

具体描述

內容簡介

  本書全麵綜述瞭形狀記憶聚閤物(SMPs)及其復閤材料的基本概念、類型、結構。此外,進一步著重介紹瞭形狀記憶聚閤物在航天、織物、生物醫藥等相關領域的應用。通過特徵鮮明的科學或工業事例,闡述瞭形狀記憶聚閤物及其復閤材料中的科學、加工和技術問題。
  本書共12章,可以分為三部分。第一部分包括第1章,主要對形狀記憶聚閤物的基本概念、結構及應用給齣瞭概述。第二部分包括中間6章,主要介紹瞭形狀記憶聚閤物及其復閤材料的結構分類、電學和熱力學特性以及其形狀記憶效應等。第三部分包括最後5章,主要闡述瞭形狀記憶聚閤物及其復閤材料的潛在應用。

作者簡介

硃輝,1975年5月生,俄羅斯族,新疆維吾爾自治區塔城市人。1995年至今在新疆塔城地區中級人民法院工作,現任新疆塔城地區中級人民法院審判委員會委員、民事審判第一庭庭長、四級高級法官。2004年獲蘭州大學法律碩士;2011年獲中南財經政法大學法學博士。在《法律適用》,《法學雜誌》、《人民法院報》、《新疆法學》等刊物上發錶學術論文多篇。

目錄

前言
編輯
編者
1 形狀記憶聚閤物的綜述 Marc Behl and Andreas Lendlein
2 形狀記憶聚閤物的結構分類 Hong-Yan Jiang and Annette M.Schmidt
3 熱力學行為和建模方法 Hang Jerry Qi and Martin L.Dunn
4 形狀記憶聚閤物(二/三-段) 的熱力學特性和建模方法 Karl Kratz,Wolfgang Wangermaier,Matthias Heuchel,and Andreas Lendlein
5 摻雜炭黑的PU形狀記憶聚閤物的電、熱力學及形狀記憶性能 Wei Min Huang and Bin Yang
6 多功能形狀記憶聚閤物及其驅動方法 Jinsong Leng,Haibao Lu and Shanyi Du
7 形狀記憶聚閤物復閤材料 Jinsong Leng,Xin Lan and Shanyi Du
8 形狀記憶聚閤物在航天領域的應用 Yanju Liu and Jinsong Leng
9 形狀記憶聚閤物泡沫及其應用 Witold M.Sokolowski
10 形狀記憶聚閤物紡織品 Jinlian Hu
11 形狀記憶聚閤物在生物醫藥領域的應用 Witold M.Sokolowski and Jinsong Leng
12 形狀記憶聚閤物的嶄新應用及未來 Wei Min Huang
索引

精彩書摘

Overview of Shape-Memory Polymers

Marc Behl and Andreas Lendlein*

Center for Biomaterial Development, Institute for Polymer
Research, GKSS Research Center, Teltow, Germany

CONTENTS

1.1 Introduction ....................................................................................................
1
1.2 Definition of Actively Moving Polymers ....................................................
2
1.3 Shape-Memory Polymer Architectures ......................................................
3
1.3.1
Thermally Induced Dual-Shape Effect ...........................................
4
1.3.1.1
Thermoplastic Shape-Memory Polymers ........................
4
1.3.1.2
Covalently Cross-Linked Shape-Memory
Polymers ...............................................................................6
1.3.2
Indirect Triggering of Thermally Induced Dual-Shape
Effect ....................................................................................................8
1.4 Light-Induced Dual-Shape Effect .............................................................. 11
1.5 Triple-Shape Polymers ................................................................................12
1.6 Outlook .......................................................................................................... 14
References ...............................................................................................................15
1.1 Introduction
The ability of polymers to respond to external stimuli such as heat or light is of
high scientific and technological significance. Their stimuli-sensitive behavior
enables such materials to change certain of their macroscopic properties such
as shape, color, or refractive index when controlled by an external signal. The
implementation of the capability to actively move into polymers has attracted
the interest of researchers, especially in the last few years, and has been
achieved in polymers as well as in gels. Sensitivity to heat, light, magnetic
fields, and ion strength or pH value was also realized in gels [1]. In nonswollen polymers, active movement is stimulated by exposure to heat or light and
could also be designed as a complex movement with more than two shapes.

* To whom correspondence should be addressed. E-mail: andreas.lendlein@gkss.de
Besides their scientifi c significance, such materials have a high innovation
potential and can be found, e.g., in smart fabrics [2?4], heat-shrinkable tubes
for electronics or films for packaging [5], self-deployable sun sails in space-
crafts [6], self-disassembling mobile phones [7], intelligent medical devices [8],
and implants for minimally invasive surgery [9?11]. These are only examples
and cover only a small region of potential applications. Actively moving polymers may even reshape the design of products [12]. In this chapter, different classes of actively moving materials are introduced with an emphasis on
shape-memory polymers. The fundamental principles of the different functions are explained and examples for specific materials are given.

1.2 Definition of Actively Moving Polymers
Actively moving polymers are able to respond to a specific stimulus by changing their shape. In general, two types of functions have to be distinguished:
the shape-memory and the shape-changing capability. In both cases, the
basic molecular architecture is a polymer network while the mechanisms
underlying the active movement differ [13,14]. Both polymer concepts contain either molecular switches or stimuli-sensitive domains. Upon exposure
to a suitable stimulus, the switches are triggered resulting in the movement
of the shaped body.

Most shape-memory polymers are dual-shape materials exhibiting two distinct shapes. They can be deformed from their original shape and temporarily
assume another shape. This temporary shape is maintained until the shaped
body is exposed to an appropriate stimulus. Shape recovery is predefi ned
by a mechanical deformation leading to the temporary shape. So far, shape-
memory polymers induced by heat or light have been reported. Furthermore,
the concept of the thermally induced shape-memory effect has been extended
by indirect actuation, e.g., irradiation with IR-light, application of electrical
current, exposure to alternating magnetic fields, and immersion in water.

Besides exhibiting two distinct shapes, an important characteristic of
shape-memory polymers is the stability of the temporary shape until the
point of time of exposure to the suitable stimulus and the long-term stability
of the (recovered) permanent shape, which stays unchanged even when not
exposed to the stimulus anymore. Finally, different temporary shapes, substantially differing in their three-dimensional shape, can be created for the
same permanent shape in subsequent cycles.

In contrast to shape-memory polymers, shape-changing polymers change
their shape gradually, i.e., shrink or bend, as long as they are exposed to
a suitable stimulus. Once the stimulus is terminated, they recover their
original shape. This process of stimulated deformation and recovery can
be repeated several times, while the geometry, i.e., of how a workpiece is
moving, is determined by its original three-dimensional shape as the effect
is based on a phase transition in a liquid crystalline elastomer network. Heat,
light, and electromagnetic fields have been reported as suitable stimuli for
shape-changing polymers.

1.3 Shape-Memory Polymer Architectures
The shape-memory effect is not an intrinsic material property, but occurs
due to the combination of the polymer’s molecular architecture and the
resulting polymer morphology in combination with a tailored processing
and programming technology for the creation of the temporary shape. To
enable the shape-memory effect, a polymer architecture, which consists of
netpoints and molecular switches that are sensitive to an external stimulus,
is required.

The permanent shape in such a polymer network is determined by the net-
points that are cross-linked by chain segments (Figure 1.1). Netpoints can
be realized by covalent bonds or intermolecular interactions; hence, they are
either of a chemical or a physical nature. While chemical cross-linking can be
realized by suitable cross-linking chemistry, physical cross-linking requires
a polymer morphology consisting of at least two segregated domains. In
such a morphology, the domains providing the second-highest thermal transition, Ttrans, act as switching domains, and the associated segments of the
multiphase polymers are therefore called “switching segments,” while the

Extension
and
cooling
Heating
Switching segment, relaxed
Netpoint
Ttrans
°C
Ttrans
°C
Ttrans
°C
Switching segment, elongated and fixed
Shape (B)

Shape (A)

Shape (B)

FIGURE 1.1

Molecular mechanism of the thermally induced shape-memory effect. Ttrans is the thermal transition temperature of the switching phase. (Adapted from Lendlein, A. and Kelch, S., Angew.
Chem. Int. Ed., 41(12), 2034, 2002. With permission.)
domains associated-to-the highest thermal transition, Tperm, act as physical
netpoints. The segments forming such hard domains are known as “hard
segments.” These switches must be able to fix the deformed shape temporarily under conditions relevant to the particular application. In addition to
switching domains, they can be realized by functional groups that are able to
reversibly form and cleave covalent cross-links. The thermal transition, Ttrans,
related to the switching domains can be a melting transition (Tm), or a glass
transition (Tg). Accordingly, the temporary shape is fixed by a solidifi cation of
the switching domains by crystallization or vitrification. In suitable polymer
architectures, these switching domains can be formed either by side chains
that are only connected to one netpoint and do not contribute to the overall
elasticity of the polymer, or by chain segments linking two netpoints and
contributing to the overall elastic behavior. In both cases, the temporary stabilization is caused by the aggregation of the switching segments. Recently,
blends of two thermoplastic polymers having shape-memory capability
were presented, in which the segments forming the hard and the switching
domains consisted of two different multiblock copolymers.

Functional groups that are able to reversibly form and cleave covalent
bonds controlled by an external stimulus can be used as molecular switches
providing chemical bonds. The introduction of functional groups that are
able to undergo a photoreversible reaction, e.g., cinnamic acid (CA) groups,
extends the shape-memory technology to light, which acts as a stimulus.

Shape-memory properties are quantified in cyclic stimuli-specifi c mechanical tests [15,16] in which each cycle consists of the programming of the test
specimen and the recovery of its permanent shape. Different test protocols
have been developed for the programming and recovery (see Chapter 3)
from which the shape-memory properties are quantified by determining the
shape-fixity ratio (Rf) for the programming and the shape-recovery ratio (Rr)
for the recovery process. In thermally induced shape-memory polymers, the
determination of the switching temperature, Tsw, characterizing the stress-
free recovery process can be included in the test protocol.

1.3.1 Thermally Induced Dual-Shape Effect
1.3.1.1 Thermoplastic Shape-Memory Polymers
An important group of physically cross-linked shape-memory polymers are
linear-block copolymers. Block copolymers with Ttrans = Tm, and where polyurethanes and polyether-ester are prominent examples for such materials, are
reviewed by Lendlein and Kelch [15]. In polyesterurethanes, oligourethane
segments act as hard segments, while polyester, e.g., poly(ε-caprolactone)
(Tm= 44°C.55°C) forms the switching segment [17?19]. The phase separation
and the domain orientation of poly(ε-caprolactone)-based polyesterurethanes
could be determined by Raman spectroscopy using polarized light [20]. In
polyesterurethanes where poly(hexylene adipate) provides the switching
segment, and a hard segment is formed by the 4,4′-diphenyldiisocyanate and
the 1,4-butanediol, the influence of the Mn of the switching segment as well
as the hard segment content on the shape-memory properties were investigated [21]. The Rf increases with the increasing Mn of the switching segment
but decreases with the increasing hard segment content. At the same time,
the Rr decreases with the increasing Mn of the switching segment and the
increasing hard segment content. Fibers from polyesterurethanes exert significantly higher recovery stress in the fiber axis when compared to the polymer
fi lms [22]. The exchange of the chain extender 1,4-butanediol with ethylenediamine can result in improved values of the Rf as urea-type bonding of the
ethylene diamine can restrict the chain rotation and strengthen the physical
interactions between the polyurethane segments [23]. Additionally, the shape-
memory properties of polyurethanes can be enhanced by the addition of a
second soft segment in small amounts so that segmented polyurethanes are
obtained; e.g., 5 wt% of poly(ethylene glycol) can be added during synthesis to
the poly(tetramethylene glycol) [24]. The addition of N-methyldiethanolamine
as a cationomer in the hard segment of the segmented polyurethanes from
poly(ε-caprolactone), 4,4′-diphenylmethane diisocyanate and 1,4-butanediol,
simultaneously improved the Rf and the Rr. This effect is attributed to an
improved switching segment crystallization [25]. A similar effect was found
in copolyester-based ionomers obtained by the bulk polymerization of adipic acid and mixed monomers of bis(poly(oxyethylene)) sulfonated dimethyl
fumarate and 1,4-butanediol [26]. The storage modulus of the rubbery plateau
was significantly increased with increasing ionomer content and recovery
rates of up to 95% were determined. Melt blending of an elastomeric ionomer
based on the zinc salt of sulfonated poly{ethylene-r-propylene-r-(5-ethylidene2-norbornene)} and low molecular mass fatty acids results in polymer networks in which the nanophase-separated ionomer provides the permanent
network physically cross-linked by the zinc salt, and the fatty acids provide
nanophases, whose melting triggers the shape recovery [27]. Polycarbonate
segments containing polyurethanes were synthesized by the copolymerization of ethylene oxide in the presence of CO2 catalyzed by a polymer-supported bimetallic catalyst, which yields an aliphatic polycarbonate diol. This
macrodiol was further processed by the prepolymer method into a shape-
memory polyurethane [28].

Thermoplastic multiblock copolymers with polydepsipeptide- and poly(εcaprolactone)-segments providing shape-memory capability were synthesized via the coupling of oligodepsipeptide diol and oligo(ε-caprolactone)
diol (PCL-diol) using a racemic mixture of 2,2,4- and 2,4,4-trimethylhexamethylene diisocyanate (TMDI). The multiblock copolymers were developed
for biomedical applications and are supposed to degrade into less harmless
degradation products than polyester-based materials. In the polymer molecules, the PCL block has the function of a switching segment forming the
switching domains, that fix the temporary shape by crystallization [29].
Recently, binary polymer blends from two different multiblock copolymers
with shape-memory capability were presented, whereby the fi rst polymer
component provided the segments forming the hard domains and the second, the segments forming the switching domains [30]. In both multiblock
copolymers, a poly(alkylene adipate) mediator segment was incorporated
to promote their miscibility as the hard segment poly(p-dioxanone) (PPDO)
and the switching segment poly(ε-caprolactone) (PCL) are nonmiscible. All
polymer blends investigated showed excellent shape-memory properties.
The melting point associated with the PCL switching domains Tm, PCL, is
almost independent of the weight ratio of the two blend components. At the
same time, the mechanical properties can be varied systematically by the
blend composition. In this way, a complex synthesis of new materials can
be avoided. This binary blend system providing good biodegradability, a
variability of mechanical properties, and a Tsw around the body temperature
is thus an economically efficient, suitable candidate for diverse biomedical
applications.

1.3.1.2 Covalently Cross-Linked Shape-Memory Polymers
Shape-memory polymer networks providing covalent netpoints can be
obtained by the cross-linking of linear or branched polymers as well as
by (co)polymerization/poly(co)condensation of one or several monomers,
whereby one has to be at least trifunctional. Depending on the synthesis
strategy, cross-links can be created during the synthesis or by postprocessing
methods. Besides cross-linking by radiation (γ-radiation, neutrons, e-beam),
the most common method for chemical cross-linking, after processing, is
the addition of a radical initiator to polymers. An example of this is the
addition of dicumyl peroxide to a semicrystalline polycyclooctene obtained
by ring-opening methathesis polymerization containing unsaturated carbon bonds [31]. Here, the shape-memory effect is triggered by the melting
of crystallites, which can be controlled by the trans-vinylene content. With
increasing cross-linking density, the crystallinity of the material decreases.
A melting temperature of 60°C was determined for pure polycyclooctene
with a 81 wt% trans-vinylene content resulting in a shape recovery of these
materials within 0.7 s at 70°C. The conversion to Ttrans, when temperature is
increased, can be monitored by the addition of a mechanochromic dye based
on oligo(p-phenylene vinylene). Previously formed excimers of the dye are
dissolved at this point and a pronounced change of their adsorption can be
observed [32].

The other synthetic route to obtain polymer networks involves the copolymerization of monofunctional monomers with low molecular weight or
oligomeric bifunctional cross-linkers. In a model system based on a styrene
copolymer cross-linked with divinylbenzene, the influence of the degree of
cross-linking on the thermomechanical properties has been investigated [33].
By increasing the amount of the cross-linker from 0 to 4 wt%, Tg increased

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