Progress in Pacific Polymer Science 2

Recent trends in research of polymer alloys are classified in (1) orthodox approach to polymer alloys and (2) singular (out-of-orthodox) approach to polymer alloys. The development in orthodox approach is reviewed on the preparative methods, the prediction of alloy morphology and the relationships between morphology and properties. As singular approach to polymer alloys, the development of molecular composites and the microcomposites are reviewed. The field of microcomposites are mentioned more in detail. The microcomposites of p-aramid film with inorganic glass or electroconductive polymers are taken up as a special topic. The rigid rodlike polymers form a film with controlled void content, having a very low critical diffusion volume at the percolation threshold, which enables the infiltration of functional monomers. Technological applications are suggested for the future based on these knowledges.

Free radical polymerization continues to attract a significant research effort and this interest is also seen in conventional free radical chemistry. A major factor in this resurgence of interest in free radicals is the recognition that free radicals reactions including polymerizations are capable of selectivity, including stereospecificity, and control not previously associated with radical systems.

My purpose in this discussion today is really two-fold — I have a dual agenda: It is to develop a dialogue on the specifics and interrelationships of the impact, critical issues and future challenges in the area of polymeric materials science and engineering and relate this to the implications of the globalization of technology and the resulting new demands on the R&D organization in an international corporation like Hoechst.

We are, indeed, in the midst of very drastic changes on a global scale. In the politics, we have just observed the landsliding development of the Soviet Union, which was triggered by the German re-unification coincided with the revolutionary developments in the Eastern Block countries. Situation in the Middle East also continues to develop.

There is an old English saying, “There’s nothing new under the sun.” We, as scientists, know that this is not true. In fact, companies who embrace that philosophy usually find themselves economically disadvantaged and often bankrupt due to the technological innovations of their competitors. A company called Photoprotective Technologies, Inc. uses as a slogan on one of their brochures, “There is something new under the sun.” And that new emanates from science and technology. The future for discovery, for the development of enabling technologies, for paradigm shifts, has never been brighter. Science and technology will never let us down. It will always be exciting, fast moving, and highly competitive.

Novel vinyl polymers were synthesized from 1,1- or 1,2-disubstituted and 1,1,2-trisubstituted ethylenes by radical polymerization. The polymers obtained consist of a rigid chain structure on account of the bulky side groups compared with flexible poly(monosubstituted ethylene)s. The substituted polymethylenes obtained from 1,2-disubstituted ethylenes such as fumaric and maleic derivatives were revealed to have new properties different from ordinary vinyl polymers. Radical polymerization behaviors of these multi-substituted ethylenes and some properties of the resulting polymers were investigated.

Under the influence of anionic catalysts, silyl ethers react with perfluorinated olefins to produce exceptionally high yields of partially fluorinated vinyl ethers. The number of vinyl fluorines substituted can be controlled for a wide variety of fluorinated olefins and silyl ethers. Application of this reaction to difunctional starting materials affords quantitative yields of condensation polymers of moderate molecular weight.Perfluoroalkylsilanes (R_fSiMe₃) have been found to be useful reagents for construction of new C-C bonds. Activated by anionic catalysts, R_fSiMe₃ react with fluorinated olefins to give perfluroalkylated olefins and Me₃SiF. Application of this new reaction to polymer syntheses leads to a variety of otherwise inaccessible structures. Only low molecular weight oligomers have been made so far, but the process is notable as a unique example of an anion-initiated perfluoroalkene oligomerization that does not produce rearranged, branched structures.

Perfectly alternating segmented, fully cyclized, poly(siloxane-imide) copolymers were synthesized and characterized as new materials. The reaction utilized the transimidization of aminopropyl terminated polydimethyl siloxane oligomers with aminopyridine capped polyimides based on oxydiphthalic anhydride and bisaniline P. The reaction was conducted in refluxing chlorobenzene at about 130°C. Transimidization processes appear to be quite rapid under these conditions, and high molecular weight copolymers were achieved in times as short as 10 minutes. The resulting copolymers could be cast or melt pressed into transparent films whose mechanical properties reflected the compositions and block molecular weights. In general, the reactions proceeded smoothly under homogeneous conditions in chlorobenzene and produced materials with glass temperatures somewhat depressed from the 240°C value of the controlled polyimide. The method allows excellent control of the microphase morphology, which is a function of block size and interaction parameters. The synthesis and characterization of these materials will be discussed and compared to the more widely studied randomly segmented copolymers which had been prepared in our labs and elsewhere.

Polymers that contain heteroelements such as phosphorus and nitrogen in the skeletal structure offer a means for extending the properties normally associated with synthetic macromolecules into areas hitherto typical of inorganic materials such as ceramics, metals, or electroactive or electro-optical solids. The polymeric molecular structure provides materials strength and flexibility, while the heteroelements provide flame resistance, radiation resistance, and access to new reactions for the linkage of electroactive or biologically interesting units to the polymer structure. In this paper synthetic pathways that provide access to such polymers are described, together with a review of structure-property relationships that provide a high level of molecular and materials design.

Polymer degradation can take many forms, chemical, photochemical, thermal and mechanical, and can affect a wide range of polymers in various ways. Although it is usual to assume that ‘polymer degradation studies’ implies the study of degradation processes that occur in pure polymers when subjected to external stimuli, the topic also includes the examination of degraded polymeric materials recovered from the field and the use of degradation as a characterisation tool. The applied nature of the research work performed at Materials Research Laboratory directs our interests in polymer degradation to the latter two categories, rather than investigation of degradation processes in pure polymers.

High-resolution carbon-13 solid state NMR spectroscopy is employed to monitor communication between the rigid and mobile domains in a polyether-polyurethane elastomer via proton magnetization transport. Results from thermal analysis and polarized optical microscopy indicate that the urethane-rich hard domains are semicrystalline and exhibit spherulitic growth that is somewhat disordered. Proton magnetization gradients are established via mobility differences between the two domains, and the ensuing spin-diffusion process is monitored via the carbon-13 nuclear manifold. Chemical structural differences between the two types of segments produce high-resolution 13C NMR signals that allow one to track interdomain communication. Magnetic spin-temperature equilibration between the two domains occurs on the 10–100 ms time scale. This is consistent with a finely dispersed array of hard and soft microphases. The polyurethane proton-spin-diffusion results are similar to those obtained for a variety of SURLYN™ and KRATON™ commercial phase-separated copolymers.

Stereocomplexes have been formed by mixing the two isotactic poly(α-methyl-α-ethyl-β-propriolactones) (PMEPL) of opposite chirality. This leads to an insoluble complex exhibiting a melting transition which is 40°C above that of the initial isotactic components. Structural differences between these samples have been determined by nuclear magnetic resonance spectroscopy and electron diffraction. It was found by NMR that the stereocomplex crystallizes in a 2₁ helical conformation whereas the corresponding isotactic chains exhibit a helical or extended chain conformation depending upon the method of sample preparation. Electron diffraction confirms these measurements with the determination of a,b and c dimensions of the orthorombic unit cells.

Application of real time pulsed NMR(RTPNMR) for the characterization of polymer systems has been reviewed and several new examples are given. They include RTPNMR of curing process of epoxy resins and crosslinking process of polydiace-tylenes. In both cases, there appear several relaxation times for spin-spin relaxation time T₂ and spin-lattice relaxation time in the rotating frame <Inline>1</Inline>. However, spin-lattice relaxation time T₁ is single for epoxy resins and from these data, heterogeneous nature of the system during curing and cross-linking are analysed. For the last example, orientation of liquid crystalline polymers under magnetic field is detected by RTPNMR at high temperatures. RTPNMR is proved to be a powerful method for characterization of polymer systems in terms of degree of molecular motion.

A number of theories for predicting non-isothermal crystallization of polymers have been proposed (1–5). Some are based on Avrami solution (2,3), others were derived independently (1,4,5). All are based on an “additivity” principle which states that the rate of crystallization at a time, t, depends on the extent of crystallization at time t, but not on the previous history (i.e., it is path independent). In this paper we present experimental results which show that, within a certain regime of cooling rates, the additivity principle applies to isotactic polystyrene. In a previous publication we have shown the same to be true for polyethylene (6).

It has been well recognized that the NMR spectroscopy is a quite powerful tool for characterizing synthetic polymers(1-3). The most important point of the NMR method for characterizing polymers is to assign the NMR spectra. Until recently, this has been done empirically by using model compounds of simple molecules and by assuming statistical model of polymerization mechanism.

Spinodal decomposition of polymer blends with critical and off-critical compositions were studied with a particular emphasis on their morphology control. This control utilizes processes which lead to pinning down of the domain growth in the mixtures. The pinning processes discussed are spontaneous pinning, physical pinning due to crystallization or vitrification, and chemical pinning. The spontaneous pinning is applicable only to the off-critical blends but the latter two pinnings are applicable to both off-critical and critical mixtures.

The anisotropic third-order nonlinear optical susceptibility χ(3) of monodomain samples of nematic solutions of poly[1,4-phenylene-2,6-benzobisthiazole], PBT, a rodlike polymer, have been studied by third harmonic generation. Corresponding measurements have also been made for isotropic solutions of PBT. A substantial off-diagonal component of χ(3)(-3ω; ω, ω, ω) is measured, resulting in the generation of an elliptically polarized third harmonic signal for a fundamental linearly polarized along the director.

Zero-shear viscosity η° and steady-state complinance J_c of poly(N-methyl-2-vinylpyridinium chloride) solutions were measured in the absence and presence of added-salt over a wide range of polymer concentration. The polymer concentration dependence of η° in semidilute regions increases with increasing added-salt concentrations C_s and almost agrees with that for non-ionic polymers in good solvents at high added-salt concentrations. J_C in dilute regions depends on molecular weight M, polymer concentration C and C_s more strongly than that of non-ionic polymer solutions, as given by Jo ∝ M-2C_s. In entangled regions, on the other hand, J_c depends on polymer concentration only in the same manner as that of non-ionic polymer solutions, but its concentration dependence is weaker than that of non-ionic polymer solutions, as given by J_e∝C-1.3. Moreover, the polymer concentration dependence of the weight-average relaxation time t_w increases with increasing added-salt concentration in the semidilute region for η° and the entangled region for J_c. These viscoelastic properties of entangled-polyelectrolyte solutions can be well explained by the reptation model assuming that the correlation lengths related to entanglements are determined by the electrostatic interactions evaluated from the Donnan equilibrium.

Polyurethane elastomers, prepared from: (i) polyether macrodiols that contain a reduced number of ether linkages compared with PTMO [poly(tetramethylene oxide)], (ii) the diisocyanate MDI [4,4’-diphenylmethanediisocyanate], and (iii) the chain extender BDO [1,4-butanediol] offer enhanced stability towards oxidation and hydrolysis over their PTMO-based counterparts. Polyurethane-ureas prepared from the diisocyanate TMXDI (m-tetramethylxylene diisocyanate), however, show decreased stability. In vivo subcutaneous implant experiments (sheep; 90 days and 180 days), show that the new MDI-based ether-reduced polyurethanes do not undergo stress cracking while the PTMO-based materials do. The TMXDI materials performed poorly when implanted.

Perfect extraction of intrinsic membrane proteins or enzymes from intact cells and reconstitution of them without any denaturation and deactivation are basic requirement in investigation of the function of membrane proteins and/or the utilization of them in membrane protein engineering. For this purpose, artificial cell, liposome, seems to be a desirable and promising tool in both basic investigation and application.

To improve the blood compatibility of commercial polyurethane (PU), PU surface was chemically grafted with a hydrophilic polyethyleneoxide (PEO) and further sulfonated to prepare PU-PEO-SO₃. The surface characteristics and blood compatibilities of surface modified PUs were investigated. PU-PEO-SO₃ surfaces showed very smoothness and complete wetting behaviors to be highly hydrophilic. The PEO-sulfonate grafted PUs were much more blood compatible than untreated PU and PU-PEO, but they exhibited a enhanced adsorption of fibrinogen compared with PU-PEO. The ex vivo occlusion times coincided well with the in vitro evaluation results: the less the adhesion and shape change of platelets and the larger the clotting times, the longer occlusion times. Such an enhanced blood compatibility of PU-PEO-SO₃ is due to the synergistic effect of the hydrophilic PEO and the negatively charged SO₃ groups on blood compatibility via a negative cilia concept.

Relationship between orientation and conductivity of polyacetylene films has been studied. Polyacetylene films were synthesized by employing both trialkyl aluminiums and tetraalkyl titanates having long alkyl chains such as hexyl, octyl or decyl groups as catalysts. These polyacetylene films showed good stretchability. The polyacetylene films are oriented by stretching. Orientation degree of polyacetylene films was evaluated by means of polarized infrared spectra. Ca. twenty time of conductivity on the polyacetylene films can be obtained by stretching compared with as-grown films. Orientation is one of the most important factors to enhance the conductivity of pi-conjugated polymers like polyacetylene.

Functional polymers are macromolecules containing functional groups (e.g. -OH, -COOH, hydrophobes) which have polarity/reactivity differences from backbone chains. Alternatively, functional polymers may be viewed as materials that have a function or a use. Functional polymers often show unusual or improved properties by virtue of enhancements in phase separation, reactivity or associations.

Recently thermotropic liquid crystalline polyarylates (TLCPs) have been attracting much attention because of their very high modulus, excellent processability, thermal resistance, dimentional stability, flame resistance and chemical resistance, and the possibility of being a substitute for Al. However, TLCPs have also some serious problems such as mechanical anisotropy, low weldline strength and fibrization (delamination), and the modulus is still lower than that of Al. We have been working on the preparation of novel TLCPs with higher weldline strength and resistance to fibrization and found that TLCPs derived from 4,4′-diphenyldicarboxylic acid(BB) would be promising materials as a substitute for Al.

In 1985, thermoplastic LCP was introduced by Mitsubishi Kasei (registered name: Novaccurate), Unitika (Rodrun) and Polyplastics (Vectra) in Japan. Hoechst Celanese also officially introduced Vectra in the US at the same time, thus 1985 can be recognized as the first year of LCP worldwide.

Copolyesters having well-defined sequential order and aromatic polyesters having regioregularly positioned substituents were successfully synthesized via multistep routes. Their properties such as thermal transitions, thermotropic properties, crystallization tendency etc. were compared with those of random sequence copolyesters and randomly substituted counterparts. The polymers of regular micro-chemical structures were found to have much higher melting transition temperatures and greater degree of crystallinity than those having irregular structures. It also was learned that positional isomerism of the substituents leads to different crystal structure.

When styrene-butadiene-styrene (SBS) block copolymers are chemically cross-linked and subsequently converted to semi or full interpenetrating networks (IPNs) by the in situ polymerization of styrene, transparent tough products can be made. The process is complicated by changes in block copolymer morphology, grafting reactions and the form of interpenetration that the polystyrene takes within the thermoplastic elastomer continuous phase. Here, changes in morphology during IPN production are monitored by transmission electron microscopy, and associated thermal behaviour shown by dynamic mechanical analysis. In tough products, changes in domain structure in the SBS occur, together with an increased miscibility between the SBS and PS.

A consideration is described on the “Properties” of materials as the basis of science and technology, in connection with my early research on textile- The “Functionality” is then discussed in some details and the stream from property to “Sensibility” is viewed through “Functionality” in my own style. Biocompatibility has been regarded as one of the functionalities of polymers and studied in our laboratory a decade ago, as one of the prestages of the sensibility or humanity concepts. Finally, the arts in science are briefly imagined in two ways; one, comprehensive approach downward (anti-clockwise, in the top part of Figure 2) from the arts to science, and the other, individual one upward (in the bottom part of Figure 2) from science to the arts.

For many years, protective garments have been worn by surgical personnel to prevent the contamination of the patient from microorganisms. More recently, medical personnel have been concerned about being exposed to diseases from the body fluids of the patient [e.g., hepatitis B (HBV), human immunodeficiency virus (HIV), and acquired immunodeficiency syndrome (AIDS)]. The Association of Operating Room Nurses and testimony at the preliminary hearings of the Occupational Safety and Health Administration have recommended that surgical gowns repel all of the body fluids typically found in the surgical setting (1,2). Consequently, the liquid barrier properties of fabrics used to produce these protective garments need to be measured so that these products can be compared by hospital personnel.

Acoustic frequency fluctuations of sound of music in general have the so-called 1/f spectrum in which power spectrum density is inversely proportional to Fourier frequency f. It was for a long time a mystery, but recently we found that this nature was closely related to physiological phenomena. Rhythmical phenomena in biology such as the heartbeat, spontaneous discharges of a neuron, clapping, the alpha rhythm observed on scalp potentials, and intervals of action potential impulses propagating on a nerve axon, have also 1/f spectrum. It is conjectured that music is unconsciously composed such that it simulates basic biological rhythm fluctuations. This coincidence suggests that external stimulations which obey 1/f fluctuations in time or in space evoke comfortable sensations.Many people share common standards of evaluations of fine art and music regardless of the fact that they live(d) in different eras, have different cultural backgrounds and religions, etc. The only possible properties they can share in common would be physiological functions. Therefore, it is likely that the sensation caused when one looks at beautiful things must be deeply related to some physiological phenomena. Based on this principle, we have generated nice musical sounds, a beautiful 3-dimensional surface, color patterns and textures from mathematically generated 1/f number sequences and 2-dimensional 1/f number arrays.

Out of the total sum of 15 billion dollars of annual textile imports, approximately 7 billion dollars are imported from Italy and France. Most of those textiles are of a good sense, and thus called as KANSEI Sho-hin, the sensible goods. Sensibility -KANSEI-can be defined in various ways as, for example: (1)Emotional capacity to respond to sensory stimuli.(2)The biggest part of human nature yet unpolished even in this day.(3)An expression to summarize the incomprehensibility of consumers’ taste.(4)A key concept to understand a future trend of commercial products.(5)An antonym to RISEI (reason, i.e., an intellectual power to evaluate physical factors).(6)A sense common to the sense of the times and life feeling.(7)Sensitivity to the significance of information.(8)An attractive condition in contrast to a necessary condition.(9)An aesthetic sense to external appearance and comfortableness (in the case of clothes).(10)Characteristics representing a symbolic value rather than a functional value.(11)A natural aptitude or a good taste for finding an aesthetic value.(12)Mental and physical agreeableness.(13)A word which is employed to distinguish one’s perspective view.(14)A capability to perceive the emotional change caused interactively.(15)An emotional wear in a sense that reason is a logical wear.(16)A movement of human mind (the sense of memory).

In 1950’s and 60’s when natural fiber materials were exhausted and synthetic polymers, invented to provide the fibers as substitute materials, had been adapted to clothings, durable and easy-care materials were essential factors for that purpose.