Ring-Opening Polymerization of l-Lactide and ε-Caprolactone Utilizing Biocompatible Zinc Catalysts. Random Copolymerization of l-Lactide and ε-Caprolactone

High-Performance Recyclable Polyester Elastomers Through Transient Strain-Stiffening

Polyester thermoplastic elastomers are promising sustainable materials but their mechanical properties need improvement, in particular, attempts to increase strength often result in compromised elasticity. Strong and tough elastomers are known but require complex polymer formulations together with control over cross-linking or crystallinity, both of which challenge recycling. Here, the introduction of transient strain-stiffening approaches into fully amorphous structures show both strengthening and toughening of elastomers while conserving recyclability. The new amorphous block polyester elastomers are prepared by controlled polymerization methods using commercial monomers. The block polymers comprise a central poly(ɛ-caprolactone-co-ɛ-decalactone) block flanked by poly(cyclohexene oxide-alt-phthalate) blocks. Elastomer thermomechanical properties are tuned by varying ratios of ɛ-caprolactone to ɛ-decalactone within the mid-block to access materials with excellent mechanical properties. The best elastomers feature 30-50 wt.% polycaprolactone and exhibit tensile strengths up to 40 MPa, elongations at break above 2000%, with excellent elastic recovery (>90%). These materials exhibit strain-induced crystallization and outperform current commercial elastomers, entering a new region of tensile mechanical property space. They have service temperature ranges from -60 to 140 °C and high temperature stability (≥300 °C), with wide thermal (re)processing windows. These new polyester elastomers also show high resistance to creep, humidity resistance, and excellent recyclability.

Crafting tailored, well-defined block copolymers of cyclic esters with an organomagnesium initiator

An organomagnesium complex containing an imino-phosphanamidinate ligand was found to be a competent catalyst for the ROP of rac-LA and ε-CL as well as their copolymerization via sequential addition of monomers, resulting in the formation of PCL-b-PLA diblock copolymer. The polymers obtained were characterized by 1H, 13C, DOSY NMR, DSC, TGA, POM, and SEM.

Selective Transesterification to Control Copolymer Microstructure in the Ring-Opening Copolymerization of Lactide and ε-Caprolactone by Lanthanum Complexes

A series of novel lanthanum amido complexes, supported by ligands designed around the salan framework (salan = N,N'-bis(o-hydroxy, m-di-tert-butylbenzyl)-1,2-diaminoethane) were synthesized and fully characterized in the solid and solution states. The ligands incorporate benzyl or 2-pyridyl substituents at each tertiary amine center. The complexes were investigated as catalysts in the ring-opening homopolymerization of lactide (LA) and ε-caprolactone (ε-CL) and copolymerization of equimolar amounts of LA and ε-CL at ambient temperature. Solvent (THF or toluene) and the number of 2-pyridyl groups in the complex were found to influence the reactivity of the catalysts in copolymerization reactions. In all cases, complete conversion of LA to PLA was observed. The use of THF, a coordinating solvent, suppressed ε-CL polymerization, while the presence of one or more 2-pyridyl groups promoted ε-CL polymerization. Each copolymer gave a monomodal trace in gel permeation chromatography-size-exclusion chromatography (GPC-SEC) experiments, indicative of copolymer formation over homopolymerization. Copolymer microstructure was found to be dependent on catalyst structure and reaction solvent, ranging from blocky to close to alternating. Experiments revealed rapid conversion of LA in the initial stages of the reaction, followed by incorporation of ε-CL into the copolymer by either transesterification or propagation reactions. Significantly, the mode of transesterification (TI or TII) that occurs is determined by the structure of the metal complex and the reaction solvent, leading to the possibility of controlling copolymer microstructure through catalyst design.

Iron(ii) carboxylates and simple carboxamides: an inexpensive and modular catalyst system for the synthesis of PLLA and PLLA-PCL block copolymers

The combination of inexpensive Fe(ii) acetate with low molecular weight aliphatic carboxamides in situ generates an effective catalyst system for the ring opening polymerisation of lactones. PLLAs were produced in melt conditions with molar masses of up to 15 kg mol-1, narrow dispersity (Đ = 1.03), and without racemisation. The catalytic system was investigated in detail with regard to Fe(ii) source, and steric and electronic effects of the amide's substituents. Furthermore, the synthesis of PLLA-PCL block copolymers of very low randomness was achieved. This commercially available, inexpensive, modular, and user-friendly catalyst mixture may be suitable for polymers with biomedical applications.

Catalysts as Key Enablers for the Synthesis of Bioplastics with Sophisticated Architectures

Bioplastics are one of the answers to environmental pollution and linear material flows. The most promising bioplastic polylactide (PLA) is already replacing conventional plastics in a number of applications. The properties of PLA, however, do not fit for all potential application areas, but they can be altered by the introduction of comonomers. The copolymerization of lactide (LA) with other lactones like ϵ-caprolactone (CL) has been established for several years. Nevertheless, controlling copolymerizations remains a challenge due to the high complexity of the system. Copolymerization of LA with other monomer classes is much less investigated, but has the chance to overcome the limitations in material properties that occur when only lactones are used. The crucial factor for all copolymerizations is the catalyst. It dominates the reaction kinetics and determines the resulting microstructure. In this review, copolymerization catalysts for LA are presented divided into catalysts for the synthesis of lactone block copolymers, lactone random copolymers, and multimechanistically synthesized copolymers. The selected catalysts are highlighted either owing to their industrially applicable polymerization conditions or their non-standard mechanism.

Controlled and effective ring-opening (co)polymerization of rac-lactide, ε-caprolactone and ε-decalactone by β-pyrimidyl enolate aluminum complexes

A series of β-pyrimidyl enolate aluminum complexes (1–6) were found to promote controlled and living ROP of rac-LA, ε-CL, and ε-DL. Six well-defined diblock copolymers and the perfect random copolymer poly(l-LA-r-CL) were successfully synthesized.

Amphiphilic Crosslinked Four-Armed Poly(lactic-co-glycolide) Electrospun Membranes for Enhancing Cell Adhesion

Common poly(lactide-co-glycolide) (i-PLGA) has emerged as a biodegradable and biocompatible material in tissue engineering. However, the poor hydrophilicity and elasticity of i-PLGA lead to its limited application in tissue engineering. To this end, an amphiphilic crosslinked four-armed poly(lactic-co-glycolide) was prepared. First, four-armed PLGA (4A-PLGA) was synthesized by polymerizing l-lactide (LA) and glycolide (GA) with pentaerythritol as the initiator. Then, the hydrophilic polymer poly(glutamate propylene ester) (PGPE) was prepared through the esterification of glutamic acid and 1,2-propanediol. The hydrophilic 4A-PLGA-PGPE was finally synthesized through the condensation reaction of 4A-PLGA and PGPE with the aid of triphosgene. 4A-PLGA-PGPE was then used to prepare amphiphilic membranes by electrospinning. It was demonstrated that the mechanical properties and biocompatibility of 4A-PLGA were improved after the introduction of PGPE. Furthermore, the introduction of glutamate improved the hydrophilicity of 4A-PLGA, thus effectively promoting cell entry and adhesion, which makes the electrospun 4A-PLGA-PGPE membranes promising for tissue engineering.

Master of Chaos and Order: Opposite Microstructures of PCL-co-PGA-co-PLA Accessible by a Single Catalyst

One catalyst, two reaction set-ups, three monomers and unlimited macromolecular microstructural designs: The iron guanidine complex [FeCl2 (TMG5NMe2 asme)] (1) polymerizes lactide faster than the industrially used Sn(Oct)2 and shows high activity towards glycolide and ϵ-caprolactone. Its distinguished features enable the synthesis of both block and random-like copolymers in the melt by a simple change of the polymerization set-up. Sequential addition of monomers yields highly ordered block copolymers including the symmetrical PLA-b-PGA-b-PCL-b-PGA-b-PLA pentablock copolymers, while polymerizations of monomer mixtures feature enhanced transesterifications and pave the way to di- and terpolymers with highly dispersed repeating unit distributions. A robust catalyst active under industrially applicable conditions and producing copolymers with desired microstructures is a major step towards biocompatible polymers with tailor-made properties as alternatives for traditional plastics on the way towards a sustainable, circular material flow.

Niobium and Tantalum complexes derived from the acids Ph2C(X)CO2H (X = OH, NH2): synthesis, structure and ROP capability

Tetranuclear [M4(OEt)8(L1)4(μ-O)2] and dinuclear [M2(OEt)4(L2H2)4(μ-O)] complexes (M = Nb, Ta) derived from benzilic acid (L1H2) and diphenylglycine (L2H3) have been structurally characterized and are capable of the ROP of μ-caprolactone and rac-lactide.

Ring-Opening Polymerization of ε-Caprolactone Mediated by Di-Zinc Complex Bearing Macrocyclic Thioether-phenolate [OSSO]-type Ligand

A unique example of zinc bromide complexes bearing macrocyclic [OSSO]-type thioetherphenolate ligand (Di-[OSSO]ZnBr) has been successfully explored toward ring-opening polymerization (ROP) of -caprolactone (ε-CL) in the presence of epoxides and...

Zinc 8-aminotrihydroquinolines appended with pendant N-diphenylphosphinoethyl arms as exceptionally active catalysts for the ROP of ε-CL

Through activation with LiCH2SiMe3 or LiN(SiMe3)2, zinc(ii) chloride complexes bearing 5,6,7-trihydroquinolin-8-amines appended with pendant diphenyl phosphine units displayed remarkable catalytic activity for ROP of ε-caprolactone.

Fabrication of Porous Crystalline PLGA-PEG Induced by Swelling during the Recrystallization Annealing Process

Poly(lactide-co-glycolide) (PLGA) has been widely used as a scaffold material for tissue engineering owing to its biocompatibility, biodegradability, and biosafety. However, lactic acid (LA) produced during PLGA degradation is prone to inflammation, which is a shortcoming that must be avoided. To this end, crystalline PLGA-PEG was synthesized here for the first time. To make the crystalline PLGA-PEG more suitable for tissue engineering, porous crystalline PLGA-PEG was prepared via the swelling behavior during recrystallization annealing. The structure and properties of the porous crystalline PLGA-PEG were confirmed by SEM, POM, and XRD. Furthermore, the swelling behavior of different PEG molecular weights was studied, and the cell viability test and alkaline phosphatase activity test showed that PLGA-PEG has good biocompatibility. Such a porous crystalline PLGA-PEG will make PLGA have a broader application prospect in bone repair.

Development of an Antimicrobial-Coated Absorbable Monofilament Suture from a Medical-Grade Poly(l-lactide-co-ε-caprolactone) Copolymer

In this study, a medical-grade poly(l-lactide-co-ε-caprolactone) (PLC) copolymer with a monomer ratio of l-lactide (L) to ε-caprolactone (C) of 70:30 mol % for use as an absorbable surgical suture was synthesized via ring-opening polymerization (ROP) using a novel soluble liquid tin(II) n-butoxide (Sn(OnC4H9)2) as an initiator. In fiber fabrication, the process included copolymer melt extrusion with a minimal draw followed by sequential controlled hot-drawing and fixed-annealing steps to obtain oriented semicrystalline fibers with improved mechanical strength. For healing enhancement, the fiber was dip-coated with "levofloxacin" by adding the drug into a solution mixture of acetone, poly(ε-caprolactone) (PCL), and calcium stearate (CaSt) in the ratio of acetone/PCL/CaSt = 100:1% w/v:0.1% w/v. The tensile strength of the coated fiber was found to be increased to ∼400 MPa, which is comparable with that of commercial polydioxanone (PDS II) of a similar size. Finally, the efficiency of the drug-coated fiber regarding its controlled drug release and antimicrobial activity was investigated, and the results showed that the coated fiber was able to release the drug continuously for as long as 30 days. For fiber antimicrobial activity, it was found that a concentration of 1 mg/mL was sufficient to inhibit the growth of Staphylococcus aureus (MRSA), Escherichia coli O157:H7, and Pseudomonas aeruginosa, giving a clear inhibition zone range of 20-24 mm for 90 days. Cytotoxicity testing of the drug-coated fibers showed a %viability of more than 70%, indicating that they were nontoxic.

Synthesis and characterization of poly(L‐lactide)‐block‐poly(ε‐caprolactone)‐grafted titanium dioxide nanoparticles via ring‐opening in situ grafting polymerization

The synthesis of nanocomposites via in situ grafting polymerization due to its ability to produce polymeric materials with promising microscopic and macroscopic characteristics is becoming very attractive. In this paper, different poly(L‐Lactide)‐block‐poly(ε‐caprolactone) (PLLA‐b‐PCL) copolymers were in situ synthesized in the presence of modified titanium dioxide (TiO2) nanoparticles (mTNP) as the initiator and stannous octoate as the catalyst. The surface of TiO2 was modified by grafting aminopropyl trimethoxy silane to improve initiator efficiency. Copolymers with 90/10, 70/30, and 50/50 mass ratio of L‐lactide/ ε‐caprolactone and 5 wt% of mTNP (proportional to ε‐caprolactone) were synthesized. The samples were characterized by HNMR, CNMR, FTIR, GPC, TGA, TEM, and DSC, confirming the successful formation of PLLA‐b‐PCL on the surface of mTNP. Tensile test results showed the synthesized nanocomposite with mass ratio of LLA/CL = 70/30 had optimum mechanical properties among other nanocomposites and also in comparison with the neat PLA.

Copolymerization of L-Lactide and ε-Caprolactone promoted by zinc complexes with phosphorus based ligands

The zinc complexes 1 and 2 bearing chelating phosphorous based pincer ligands were found to catalyze the ring-opening copolymerization of L-lactide and ε-caprolactone in the melt at 110 °C to obtain a series of random copolymers in which the monomer distributions were coherent with the monomer ratio in the feed. All the obtained copolymers showed high molecular masses with monomodal and moderately narrow distributions. The thermal properties of the achieved copolymers (T_g, glass transition temperature, and T_m, melting temperature) were strongly dependent on their composition. A linear dependence of T_g with molar percentage of lactide in the copolymers was observed over a temperature range from -59 °C (pure polycaprolactone) to 55 °C (pure polylactide).

Synthesis of Ultrahigh Molecular Weight PLAs Using a Phenoxy-Imine Al(III) Complex

l- and d-lactide polymerization kinetics using phenoxy-imine ligands of the type Me2Al[O-2-tert-Bu-6-(C6F5N=CH)C6H3] in the presence of n-butanol and benzyl alcohol by ring-opening polymerization into polylactide are investigated. Effects of initiator concentration, catalyst concentration, polymerization temperature, and time on the molecular weight of poly-l-lactide are also investigated. Purification and drying of l-lactide are found to significantly influence the polymerization kinetics and the final molecular weight achieved. Ultrahigh molecular weight poly(l-lactic acid) PLLA (M w = 1.4 × 106 g/mol with Đ = 1.8) and ultrahigh molecular weight poly(d-lactic acid) PDLA (M w = 1.3 × 106 g/mol with Đ = 2.0) are obtained when polymerization is performed with a molar ratio of monomer to catalyst (LA/Al) of 8000 for 72 h at 120 °C in the presence of benzyl alcohol with conversions of 96 and 91%, respectively. We report for the first time the synthesis of ultrahigh molecular weight poly-l- and d-lactide using the Me2Al[O-2-tert-Bu-6-(C6F5N=CH)C6H3] catalyst. The identified catalyst is found to be suitable for the synthesis of a broad range of molecular weights.

Synthesis and characterization of guanidinate tin(ii) complexes for ring-opening polymerization of cyclic esters

Novel homoleptic and heteroleptic (guanidinate)tin(ii) complexes were successfully synthesized and structurally characterized. The first heteroleptic (guanidinato)tin(ii) alkoxide complex was synthesized but found to be unstable leading to the corresponding bis(guanidinate)tin(ii) complex. The catalytic activities of bis(guanidinate)tin(ii) complexes having different substituents at the nitrogen atoms (isopropyl (1), cyclohexyl (2), and p-tolyl (3)) were investigated in the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) and lactide (LA). The lone-pair electrons of the tin(ii) atom were proposed to act as an initiator similar to N-heterocyclic carbenes. Among the synthesized catalysts, complex 1 having less steric hindrance efficiently catalyzed both homo- and copolymerizations of ε-CL and LA giving high molecular weight cyclic polyesters. Transesterification was found to be the major contributor to the cyclization to cyclic polyesters.

Lanthanum complexes stabilized by a pentadentate Schiff-base ligand: synthesis, characterization, and reactivity in statistical copolymerization of ε-caprolactone and l-lactide

Developing catalysts that are capable of catalyzing the copolymerization of ε-caprolactone and l-lactide to give random CL/LA copolymers is of great importance. One-pot reaction of La[N(SiMe₃)₂]₃ with 1 equiv. of LH₂ (LH₂ = NH(CH₂CH₂N[double bond, length as m-dash]CHC₆H₂-3,5-^tBu₂-2-OH)₂) in THF at room temperature, followed by protolysis with one equivalent amount of ROH (R = C₆H₂-2,6-^tBu₂-4-CH₃, ^tBu, ⁱPr, Bn, and Et) at 60 °C gave the mono-Schiff-base-ligated lanthanum aryloxide complex LLa(OC₆H₂-2,6-^tBu₂-4-CH₃)(THF) (1), and lanthanum alkyloxide complexes LLaO^tBu(THF) (2), [LLaOⁱPr]₂ (3), [LLaOBn]₂ (4), and [LLaOEt]₂ (5) in 59-69% isolated yields. These lanthanum complexes were capable of initiating the homopolymerization of l-lactide and rac-lactide with extremely high activity, and the copolymerization of ε-caprolactone (ε-CL) and l-lactide (l-LA) to give statistical CL/LA copolymers via a transesterification reaction.

Redox-switchable ring-opening polymerization by tridentate ONN-type titanium and zirconium catalysts

A study designed to ascertain the impact that ligand symmetry, number of redox-active moieties, and identity of the active metal center have on the catalytic ring-opening polymerization performance of redox-switchable catalysts.

Application of Diethylzinc/propyl Gallate Catalytic System for Ring-Opening Copolymerization of rac-Lactide and ε-Caprolactone

Biodegradable polyesters gain significant attention because of their wide potential biomedical applications. The ring-opening polymerization method is widely used to obtain such polymers, due to high yields and advantageous properties of the obtained material. The preparation of new, effective, and bio-safe catalytic systems for the synthesis of biomedical polymers is one of the main directions of the research in modern medical chemistry. The new diethylzinc/propyl gallate catalytic system was first used in the copolymerization of ε-caprolactone and rac-lactide. In this paper, the activity of the new zinc-based catalytic system in the copolymerization of cyclic esters depending on the reaction conditions was described. The microstructure analysis of the obtained copolyesters and their toxicity studies were performed. Resulted copolyesters were characterized by low toxicity, moderate dispersity (1.19–1.71), varying randomness degree (0.18–0.83), and average molar mass (5300–9800 Da).

Preparation of star-shaped functionalized polylactides by metal porphyrin complexes as both catalysts and cocatalysts

Several aluminum porphyrin complexes as catalysts and a copper porphyrin complex as a cocatalyst were prepared. These complexes were characterized by 1H NMR and elemental analysis. These complexes are used for L-lactide polymerization. The kinetic data of the polymerization using complex 2 as catalyst revealed that the polymeric rates were first-ordered in both the monomer and catalyst. There is a linear relationship between lactide conversion and the number-averaged molecular weight of PLA.

A Strategy of In Situ Catalysis and Nucleation of Biocompatible Zinc Salts of Amino Acids towards Poly(l-lactide) with Enhanced Crystallization Rate

The intrinsic drawback of slow crystallization rate of poly(l-lactide) (PLLA) inevitably deteriorates its final properties of the molded articles. In this work, we proposed a new strategy towards poly(l-lactide) with enhanced crystallization rate by ring opening polymerization (ROP) of l-lactide (l-LA) catalyzed by biocompatible zinc salts of amino acids. For the first time we developed a one-pot facile method of zinc salts of amino acids acting dual roles of catalysis of l-LA polymerization and in situ nucleation of the as-prepared PLLA. Nine zinc salts of different amino acids, including three kinds of amino acids ligands (alanine, phenylalanine, and proline) with l/d-enantiomers and their equimolar racemic mixtures, were first prepared and tested as catalysts of l-LA polymerization. A partial racemization was observed for zinc salts of amino acids whereas no racemization was detected for the reference stannous octoate. The polymerization mechanism study showed that the interaction of zinc salts of amino acids and benzyl alcohol forms the actual initiator for l-LA polymerization. Isothermal crystallization kinetics analysis showed that the residual zinc salts of amino acids exhibited a significant nucleation effect on PLLA, evidenced by the promotion of the crystallization rate, depending on the amino acid ligand and its configuration. Meanwhile, the residual zinc salts of amino acids did not compromise the thermal stability of the pristine PLLA.

A versatile strategy for the synthesis and mechanical property manipulation of networked biodegradable polymeric materials composed of well-defined alternating hard and soft domains

Networked materials composed of well-defined alternating domains of two types of biodegradable polymers, hard poly(l-lactide) and soft poly(ε-caprolactone), were successfully synthesized.

Bimetallic and trimetallic zinc amino-bis(phenolate) complexes for ring-opening polymerization of rac-lactide

Di- and trinuclear zinc complexes of an amino-bis(phenolate) ligand show good lactide polymerization activity in both solution and melt.

Zinc and Magnesium Complexes Bearing Oxazoline-Derived Ligands and Their Application for Ring Opening Polymerization of Cyclic Esters

A family of different substituents aza(oxazoline) ligand-based zinc and magnesium complexes were synthesized. These complexes can catalyze ring opening polymerization of ε-caprolactone (ε-CL) and lactide (LA) to produce poly-ε-caprolactone and polylactide with good conversions. Polymerization studies showed that the zinc complexes 1a-4a had moderate activity toward LA and ε-CL polymerization. In situ IR spectroscopy research of zinc complexes showed that the N-donor group-substituted complexes had higher activity than that of the O-ether donor group. The substituted analogies and the flexibility of the amino backbone had a distinct influence on the activity of LA and ε-CL polymerization. The alternates of zinc with magnesium produced complexes 5a-8a, which achieved an obviously increased polymerization activity. Among these magnesium complexes, 7a showed the highest activity in the polymerization of LA. At [M]/[cat] = 1000, the reaction progress was stabilized in 5 min with up to 97% conversion of a monomer at ambient temperature.

Catalytic metal-based systems for controlled statistical copolymerisation of lactide with a lactone

A comprehensive survey of the recent developments of metal-based catalysts for the ROcoP of lactide with another lactone is presented.

Mixed Allyl Rare-Earth Borohydride Complexes: Synthesis, Structure, and Application in (Co-)Polymerization Catalysis of Cyclic Esters

A series of new trivalent rare-earth allyl-borohydride complexes with the formula [RE(BH₄ )₂ (C₃ H₅ )(thf)_x ] (RE=Sc (1), x=2; RE=Y (2) and La (3), x=3) were synthesized by reaction of the corresponding rare-earth trisborohydrides [RE(BH₄ )₃ (thf)_x ] with half an equivalent of bis(allyl)magnesium. The complexes were fully characterized by determining their X-ray structure. Similar to their previously described Nd (4) and Sm (5) analogues, these complexes display a monomeric structure with two terminal trihapto BH₄ groups, one π-η³ allyl ligand, three THF molecules for complexes 2 and 3, and two THF molecules for complex 1. The catalytic behavior of complexes 1-5 toward the ring-opening polymerization (ROP) of l-lactide (l-LA) and ϵ-caprolactone (ϵ-CL) was assessed. The Nd complex featured the best activity toward l-LA (turnover frequency (TOF)=1300 h^-1 ) and the order was Nd>La>Sm>Y>Sc. Complexes 1-3 were found very active for the ROP of ϵ-CL (TOF=166 000 h^-1 ), which is in line with the already established exceptionnally high performance of complexes 4 and 5. With both monomers, it was shown that the borohydride moiety was the preferentially initiating group, rather than the allyl one. The random copolymerization of l-LA and ϵ-CL was performed with complexes 1-5, in the absence or in the presence of benzyl alcohol as a chain-transfer agent, affording copolymers with ϵ-caprolactone up to 62 % inserted. The copolymers synthesized display a variety of microstructures, that is, blocky, random, or quasi-alternating.

Mechanical properties and state of miscibility in poly(racD,L-lactide-co-glycolide)/(L-lactide-co-ε-caprolactone) blends

Polymers based on lactic acid (PLA) are a very promising category of biopolymers. As they are multi-stimuli responsive, can, in many ways, positively interact with the host, stimulating the innate reparative machinery of the human body. Since biopolymers for medical applications are subject to restrictive regulations, blending stands out as an effective method for obtaining tailored properties within a reduced time to market if compared to synthesis. Hence, in this study a set of PDLGA/PLCL blends was obtained by means of thermoplastic techniques and then further characterized. Evaluation techniques include GPC, NMR, DSC, tensile testing and SEM. Although mixtures proved to be immiscible, a full range of tensile properties was achieved. Observation of the surfaces of fracture provided visual evidence of the deformation mechanisms that occurred during the tensile tests which in the end led to failure. Interpretation of the thermal events based on molecular characterization parameters revealed phase separation, crystallization and plasticisation mechanisms that are relevant to any potential applications based on mechanical performance and shape memory behaviour.