Polyisoprene telechelic

Scheme 22 Synthesis of telechelic acetoxy-terminated cis- 1,4-polyisoprene by olefin metathesis depolymerization of natural rubber [144]...

The functionality of hydroxy-telechelic polybutadiene and polyisoprene was determined by -NMR after modification with phenyl isocyanate or naphthyl isocyanate. Liquid telechelic polybutadiene and polyisoprene, prepared by choosing appropriate reaction conditions, showed Fn value of about 1.9, which agreed with the values determined by titration method [69]. 

Amino-terminated telechelic polybutadiene was prepared by LiAlH4 reduction of amidino end-group in polybutadiene, which was polymerised by a water-soluble initiator, 2,2 -azobis(amidinopropane)dihydrochloride. The structure was analysed by 1H- and 13C-NMR, but functionality of 2.0 was obtained by a titration method [70]. Synthesis of co-epoxy-functionalised polyisoprene was carried out by the reaction of 2-bromoethyloxirane with living polymer that was initiated with sec-butyl lithium. The functionality of the resulting polyisoprene was 1.04 by 1H-NMR and 1.00 by thin layer chromatography detected with flame ionisation detection [71]. 

Elastomers are prepared by chain extension of hydroxyl-terminated low-molecular-weight polymers followed by vulcanization 180). The most important work concerns the use of hydroxy telechelic polybutadienes and polyisoprenes in the tire industry 249 252>. The hydroxylated polydienes of molecular weight 1000-20000 are mixed with a diisocyanate, a catalyst, vulcanization agent (sulfur), and accelerator, reinforcing additives (carbon black), and surface-active agents. The reaction takes place in two steps simultaneously or consecutively ... 

Synthesis and Characterization. The synthesis of carboxy-telechelic polyisoprenes was carried out as described previously[7], in tetrahydrofuran at -78°C using sodium naphthalide as initiator. Approximately 2-3 units of a-methylstyrene per living end were added after completion of the Isoprene polymerization to reduce the reactivity of the chain ends, which were then terminated by the addition of gaseous... 

Figure 1. Stress-strain behavior of carboxy-telechelic polyisoprenes, (a) Ca and Sr, (b) nP, Zn, and Cd. (Reprinted from ref. 11. Copyright 1988 American Chemical Society.)...

Figure 1. Desmeared, background-subtracted SAXS patterns for carboxy-telechelic polyisoprenes. Curves are offset 1200 intensity units for clarity.

Polymer Preparation. Two bifunctional (telechelic) polymers were used in this study. Carboxy-telechelic polybutadiene (PB) is commercially available from B. F. Goodrich (Hycar CTB 2000X156) with molecular characteristics of Mn=4,600, Mw/Mn= 1.8, functionality 2.00 and cis/trans/vinyl ratio of 20/65/15. Carboxy-telechelic polyisoprene (PIP) was prepared by anionic polymerization in THF at -78°C with a-methylstyrene tetramer as a difunctional initiator. The living macrodianions were deactivated by anhydrous carbon dioxide. Five polymers werejjrepared with Mn=6,000 10,000, 24,000, 30,000 and 37,000 having Mw/Mn=sl.l5 a microstructure ratio of 3, 4/1, 2 of 65/35, respectively, and a functionality >1.95. 

Polyisoprene/PS/telechelic polyisoprene diamine/telechelic PS dianhydride Internal mixer/SEM/evolution of domain size/effects of telechelic polymer MW and loading Ashcraft et al. 2009... 

The carboxy telechelic PBD commercialized by BF Goodrich un r trade mark ycw CTB 2000 x 156 was lai ely used in this work (M ) = 4,600 Myy/Mn = 1.8 functionality = 2.01 and microstructure cis/trans/vinyl = 20/65/15). Carboxy telechelic polyisoprene (PIP), poly a-methylstyrene (PMS) and poly tert.butylstyrene (PTBS) were prepared by anionic polymerization in THF at -78°C. 

Sadaka, F., Campistron, I., Laguetre, A., Pilard, J.F. Telechelic oligomers obtained by metathetic degradation of both polyisoprene and styrene-butadiene rubbers. Appl. Recycl. Waste Tire Rubber 98, 736-742 (2013)... 

Interestingly, K-TEMPO probes in monoionic block copolymers of type polystyrene-polyisoprene (notation PS-PI-S, where S stands for the spin probe) exhibited homogeneous dynamics, ie, a relatively narrow, monomodal distribution of rotational correlation times by contrast, the same probes in zwitterionic block copolymers of type Q-PS-PI-S (where Q stands for a quaternary ammonium group) exhibited heterogeneous dynamics, ie, a bimodal distribution of rotational correlation times (87). By comparison of results for telechelic homopolsrmeric... 

Fig. 12. Ionic clusters in telechelic ionomers based on diblock copolsmiers (see also Fig. 11). (a) Spin probes attached to ionic clusters located at the interface between the polystsrrene (PS) and polyisoprene (PI) microphases. The inset shows the CW ESR spectrum for PS-Q-PI, where Q is a quaternary ammonium group. The fast component (arrows) was assigned to probes in the PI microphase, (b) The distribution of ionic clusters in monoionic diblock copolymers suggested by DEER experiments, (c) The distribution of ionic clusters in zwit-terionic diblock copolymers suggested by DEER experiments.

MercaptO End Groups. Living polystyrene reacts quantitatively with thiirane to form terminal mercapto groups (168). Termination with thiirane was also used for the formation of telechelic polyisoprene containing SH end groups. 

Tg measurements have been performed on many other polymers and copolymers including phenol bark resins [71], PS [72-74], p-nitrobenzene substituted polymethacrylates [75], PC [76], polyimines [77], polyurethanes (PU) [78], Novolac resins [71], polyisoprene, polybutadiene, polychloroprene, nitrile rubber, ethylene-propylene-diene terpolymer and butyl rubber [79], bisphenol-A epoxy diacrylate-trimethylolpropane triacrylate [80], mono and dipolyphosphazenes [81], polyethylene glycol-polylactic acid entrapment polymers [82], polyether nitrile copolymers [83], polyacrylate-polyoxyethylene grafts [84], Novolak type thermosets [71], polyester carbonates [85], polyethylene naphthalene, 2,6, dicarboxylate [86], PET-polyethylene 2,6-naphthalone carboxylate blends [87], a-phenyl substituted aromatic-aliphatic polyamides [88], sodium acrylate-methyl methacrylate multiblock copolymers [89], telechelic sulfonate polyester ionomers [90], aromatic polyamides [91], polyimides [91], 4,4"-bis(4-oxyphenoxy)benzophenone diglycidyl ether - 3,4 epoxycyclohexyl methyl 3,4 epoxy cyclohexane carboxylate blends [92], PET [93], polyhydroxybutyrate [94], polyetherimides [95], macrocyclic aromatic disulfide oligomers [96], acrylics [97], PU urea elastomers [97], glass reinforced epoxy resin composites [98], PVOH [99], polymethyl methacrylate-N-phenyl maleimide, styrene copolymers [100], chiral... 

Richards" showed that living PS reacts quantitatively with thiirane to form terminal thioalkoxide groups. Morton et al. showed that this process can also be used successfully to synthesize telechelic polyisoprene containing -SH end groups." ... 

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