Polyurethane Networks Research Articles

Design and fabrication of shape memory polyurethane network with rapid recoverable plastic deformation

The flexible polymer substrate brings the possibility of recycling and reusing to the disposable electronics. Thus, it is necessary to explore a strategy to realize the structural reconfigurability and then improve the service life of polymers. Plastic deformation is one of key issues in failure of materials. Shape memory polymers (SMPs) with specific block structures are capable of remembering permanent shapes responding to various external stimuli. This excellent property is expected to contribute to the research of recoverable plastic deformation. In this work, a kind of plastic deformation-recovery shape memory polyurethane (PR-SMPU) was synthesized through bulk polymerization, where the semi-crystalline polycaprolactone (PCL) serves as soft segment and stimuli-responsive phase to achieve the recoverable character. By characterizing the mechanical properties and thermal stability, material with 40 wt% hard segment was selected, of which the breakage elongation ratio is 1126% at 20 °C and 1070% at 60 °C, the thermal stability can be guaranteed below 250 °C, and the plastic deformation can be recovered at 60 °C within 3 s. By analyzing the in-situ microstructural evolution in the constrained recovery after both elastic and plastic deformation, the mechanism of the recoverable plastic deformation of the proposed PR-SMPU were explored.

Rapidly synthesized, self-blowing, non-isocyanate polyurethane network foams with reprocessing to bulk networks via hydroxyurethane dynamic chemistry

Polyurethanes are produced from reactions of isocyanates with alcohols and are most commonly made as cross-linked networks to produce foams. Polyhydroxyurethanes (PHUs) are non-isocyanate polyurethane (NIPU) materials with promising potential as benign alternatives to isocyanate-based polyurethanes. We have developed a rheology-guided, rapid preparation of reprocessable self-blowing PHU foams by decoupling the aminolysis and thiol-decarboxylation of cyclic carbonates, allowing for dramatic reduction of reaction times from 20 h to 30 min to achieve foams without sacrificing morphological and physical properties. We studied the structure–property relationships in network PHU foams by systematically varying the thiol concentrations and demonstrated highly tunable morphological properties, including cell density, cell diameter, and open-cell ratio, and mechanical properties associated with semi-rigid and flexible foams. To address the sustainability challenges of network foams, the dynamic covalent PHU foams were melt-reprocessed into bulk films with full recovery of cross-link density. We further found that the relative modulus–relative density relationship of our foams obeys the cubic cell model proposed by Gibson and Ashby, which was applied to predict and tailor properties of new PHU foams. This study highlights the design and rapid synthesis of highly tunable and dynamic PHU foams with promising sustainability aspects.

The impact of the polycaprolactone content on the properties of polyurethane networks

The influence of soft segment (SS) content on the properties of novel polyurethane networks (PUNs), prepared by a two-step polymerization in a solvent mixture, was investigated in this work. Hyperbranched polyester of the third pseudo generation (BH-30) was used as a crosslinker, and together with isophorone diisocyanate (IPDI) was applied to build hard segments (HS) in PUNs. On the other hand, SS of the prepared PUNs are based on polycaprolactone (PCL). The content of SS in PUNs varied from 10 to 50 wt%. The structural, thermal and mechanical properties, swelling behavior, as well as morphology of PUNs, were explored by various experimental methods. Performed investigations have shown that the use of BH-30 led to the emergence of relatively high crosslinking density and good mechanical properties, and that all features of PUNs significantly depend on the SS content. Higher PCL content caused presence of certain crystallinity, better thermal stability, more pronounced microphase separated morphology, but also lower degree of hydrogen bonding, crosslinking density and storage modulus of the prepared PUNs. The obtained results have shown that the properties of PUNs can be easily varied and customized to different practical needs.

Crosslinked reprocessable phosphor/polyurethane composite networks with thermal induced self-healing capacity and ultraviolet conducted fluorescence effect

In recent years, self-healing materials have attracted extensive attentions, however, the low elasticity have limited their applications, and it is difficult to track their healing process on macroscale. Herein covalently crosslinked polyurethane (PU) composite networks were developed with thermal induced self-healing capability and ultraviolet (UV) initiated fluorescence effect, which were synthesized by polytetrahydrofuran glycol (PTMG) as soft segment, hexamethylene diisocyanate (HDI) as hard segment, incorporating with blue phosphate (BP) of SrAl2O4 doped with Eu2+, Dy3+. The physio chemical properties and self-healing process of polyurethane were studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD), atomic force microscope (AFM), optical microscope (OM), dynamic mechanical analysis (DMA) and tensile test. The results showed that the network materials were successfully developed with high elastic tensile properties. After healing at 60 °C for one hour, the PU network demonstrated a high healing efficiency and elongation at break. Moreover, the obtained hybrid networks emitted an intense blue light under UV with high fluorescent intensity to track healing process. Additionally, the synergistic effect of transesterification of dynamic hydrogen bond provided the composite networks reproducibility for recycling use. This self-healing polyester material shows promising applications in the fields of diagnostic healing and optoelectronic components.

N-Sulfonyl Urethanes to Design Polyurethane Networks with Temperature-Controlled Dynamicity

(Re)processing of cross-linked polyurethanes (PUs) is often energy intensive and inefficient since dissociation of urethane linkages at elevated temperatures generates highly reactive isocyanate moieties that can react with a wide range of nucleophiles. In this study, we first show with a small molecule study that the introduction of N-sulfonyl urethane bonds leads to dynamic covalent exchange reactions under much milder conditions compared to regular urethane groups. Then, these exchangeable N-sulfonyl urethane motifs have been introduced, in relatively small amounts (5, 10, and 20%), in a cross-linked PU matrix in an attempt to facilitate plastic flow at lower temperatures. Rheological analysis of the elastomeric dissociative networks revealed an interesting double relaxation behavior, even for temperatures between 150 and 100 °C, which could be described by a Maxwell model with two elements, which can be related to the activated and less activated urethane bonds. Finally, the (re)processability of these sulfonyl urethanes containing PUs was demonstrated through multiple cutting and hot pressing cycles and the corresponding materials showed a good retention of thermal properties.

Rigid polyurethane foams refined by the lignin oligomers from catalytic upstream biorefining process

Bio-rigid polyurethane foams (RPFs) were synthesized using the poplar sawdust lignin oligomers that were fractionized by catalytic upstream biorefining (CUB) as the substitute of unsustainable petrol-based polyols. On this basis, as the primary hydroxyl group providers for the RPFs, the lignin oligomers were isolated from the crude CUB oils that were obtained using the pulping liquors with different n-propanol/H2O ratios. Results demonstrated the CUB lignin oligomers were generally possessed low molecular weight, good miscibility, and high hydroxyl groups content, irrespective of the pulping liquor constituents, affording to highly cross-linked polyurethane networks. Moreover, the CUB pulping liquor's composition and the lignin oligomer substitution rate were proved as two decisive factors to the morphology and mechanical properties of the resulted RPFs. Compared to other groups, the RPF substituted with the lignin oligomers obtained from R7/3 (refer to n-propanol/H2O of 7/3 (v/v) in the pulping liquor) and a polyol substitution rate of 30% exhibited better mechanical properties and a highly assembled nanosized lignin complex. Additionally, the compressive strength and the apparent density of RPFs were highly dependent on the hydroxyl group content in CUB lignin oligomers, while the inner-molecular bonds such as the syringyl/guaiacyl ratios and β-O-4 bonds were also affected to the compressive strength of RPFs. The RPFs prepared by CUB lignin oligomer in the current work provides a foundation for future valorization of the side-streams from lignin-first biorefining processes.

Catalyst-Free Synthesis of Covalent Adaptable Network (CAN) Polyurethanes from Lignin with Editable Shape Memory Properties.

Here a new strategy of catalyst-free direct synthesis of covalent adaptable network polyurethanes (LPUs) from lignin with editable shape memory effect is reported. Using unmodified lignin, PEG, and isocyanate under the condition of the isocyanate index less than 1.0 (NCO/OH<1.0), a variety of LPUs are obtained. When NCO/OH=0.8, a stable cross-linked network can be formed (ex. the gel content of LPU50-0.8 was 98±0.3 %). The activation energy (Ea ) value of LPUs is similar to that of polyhydroxyurethanes (PHUs), at around 110 kJ mol-1 . With an increase of lignin content, the LPUs show a transition from ductile fracture to brittle fracture mode. And the mechanical properties of LPUs are significantly enhanced after extrusion processing, with the maximum modulus reaching 649±26 MPa and the maximum toughness up to 9927±111 kJ m-3 . The improvement in mechanical properties is due to the homogenization of complex cross-linked network under the powerful external force of the extruder and the lignin that originally was free in the system participated in the exchange reactions. Moreover, LPUs can also be prepared continuously in one step by using an extruder as the reactor. In addition, LPU50-0.8 has an editable shape memory effect. This study develops a novel method for the synthesis of LPU from lignin with NCO/OH<1.0, showcasing new possibilities for value-added utilization of lignin, and expands the bio-based products portfolio from biomass feedstock to help meet future green manufacturing demands.

Preparation of dynamic polyurethane networks with UV-triggered photothermal self-healing properties based on hydrogen and ion bonds for antibacterial applications

• The building of Zn-dimethylglyoxime-polyurethane coordination complex provides a covalently cross-linked elastomer with triple dynamic bonds. • The self-healing behavior and mechanism of 3D micro-crack is investigated by molecular dynamics simulations. • The doping of copper on double-nut shaped zinc oxide generates more defects, preventing the recombination of photo-induced electron-hole pairs and generating more heat through lattice vibration. • The enhanced self-healing effect of UV-light-responsive polyurethane was due to the hybrid of Cu-doped ZnO, which provides coordination bonds and the photothermal effect. Photo-induced self-healing composites have attracted more and more attention as a kind of materials that can be controlled remotely and accurately in real time. Here, we report a strategy of a photo-responsive system based on hydrogen and ion bonds capable of performing self-healing process by ultraviolet wavelengths, which is covalently cross-linked zinc-dimethylglyoxime-polyurethane coordination network with triple dynamic bonds. The recombination of hydrogen bond and metal coordination bond produces effective healing performance. The self-healing behavior and temperature dependence of 3D micro-crack is investigated by molecular dynamics simulations to reveal the mechanism of self-healing at molecular level. Moreover, the hybrid of copper-doped zinc oxide not only provides metal coordination bonds to enhance the self-healing rate, but also enhances the photothermal effect and anti-bacterial properties of polyurethane. Importantly, doping of copper generates more defects and forms a space charge layer on the surface of zinc oxide. The defects could trap surface electrons and holes, preventing the recombination of photo-induced electron-hole pairs, generating more heat through lattice vibration. Therefore, under ultraviolet light irradiation, the polyurethane can reach 62.7°C for 60 s, and the scratches of the polyurethane can be healed within 30 min and fully healed within 1 h.

THE STUDY OF INTERMOLECULAR INTERACTIONS IN THE POSS-CONTAINING NANOCOMPOSITES BASED ON POLYURETHANE AND POLYURETHANE/POLY(HYDROXYPROPYL METHACRYLATE) MATRICES

The nanocomposites based on polyurethane matrix and multicomponent polymer matrices consisting of polyurethane and poly(hydroxypropyl methacrylate) with different contents of the last, and 1,2-propanediolisobutyl polyhedral oligomeric silsesquioxane (1,2-propanediolisobutyl-POSS), which was used as a functionalized nanofiller, were synthesized. The influence of the content of 1,2-propanediolisobutyl-POSS on intermolecular interactions and structural features of the nanocomposites was investigated by the method of IR-spectroscopy with Fourier transformation and attenuated total reflection (FTIR-ATR). The study of thermal curing of the model system, which consists of the adduct of trimethylolpropane with toluene diisocyanate and 1,2-propanediolisobutyl-POSS, made it possible to conclude that 1,2-propanediolisobutyl-POSS participates in the reaction of urethane formation using of one of the terminal hydroxyl groups, and it is incorporated into the polymer chain between cross-linking of polyurethane networks. The investigation of multicomponent polymer matrices by FTIR-ATR spectroscopy was done and was shown that photopolymerization of second polymer poly(hydroxypropyl methacrylate) in the matrix of polyurethane was completed by the opening of a double bond and the formation of a linear polymer in the composition of semi-IPN. Studies of nanocomposites based on multicomponent polymer matrices consisting of polyurethane and poly(hydroxypropyl methacrylate) with 15 and 30 % of the last by FTIR-ATR spectroscopy demonstrated the presence of POSS in the nanocomposites and the influence of POSS content on the structure of the studied systems and on the degree of phase separation. The POSS is "embedded" into the polymer chain between cross-linking of the polyurethane networks, with the additional formation of a complex system of intermolecular hydrogen bonds between the carboxyl and amine components of urethane groups in the nanocomposites.

Water‐Induced Self‐Blown Non‐Isocyanate Polyurethane Foams

AbstractFor 80 years, polyisocyanates and polyols were central building blocks for the industrial fabrication of polyurethane (PU) foams. By their partial hydrolysis, isocyanates release CO2 that expands the PU network. Substituting this toxic isocyanate‐based chemistry by a more sustainable variant—that in situ forms CO2 by hydrolysis of a comonomer—is urgently needed for producing greener cellular materials. Herein, we report a facile, up‐scalable process, potentially compatible to existing infrastructures, to rapidly prepare water‐induced self‐blown non‐isocyanate polyurethane (NIPU) foams. We show that formulations composed of poly(cyclic carbonate)s and polyamines furnish rigid or flexible NIPU foams by partial hydrolysis of cyclic carbonates in the presence of a catalyst. By utilizing readily available low cost starting materials, this simple but robust process gives access to greener PU foams, expectedly responding to the sustainability demands of many sectors.

Water-Induced Self-Blown Non-Isocyanate Polyurethane Foams.

For 80 years, polyisocyanates and polyols were central building blocks for the industrial fabrication of polyurethane (PU) foams. By their partial hydrolysis, isocyanates release CO2 that expands the PU network. Substituting this toxic isocyanate-based chemistry by a more sustainable variant-that in situ forms CO2 by hydrolysis of a comonomer-is urgently needed for producing greener cellular materials. Herein, we report a facile, up-scalable process, potentially compatible to existing infrastructures, to rapidly prepare water-induced self-blown non-isocyanate polyurethane (NIPU) foams. We show that formulations composed of poly(cyclic carbonate)s and polyamines furnish rigid or flexible NIPU foams by partial hydrolysis of cyclic carbonates in the presence of a catalyst. By utilizing readily available low cost starting materials, this simple but robust process gives access to greener PU foams, expectedly responding to the sustainability demands of many sectors.

Sustainable Polyurethane Networks with High Self‐Healing and Mechanical Properties Based on Dual Dynamic Covalent Bonds

AbstractHydroxy‐terminated polybutadiene (HTPB) based polyurethanes (PU) networks are broadly applied in industry and aviation, however, their nonrecyclability leads to the waste of petroleum. In this work, a series of novel self‐healing, weldable, and recyclable HTPB‐based PU networks with dual reversible covalent bonds are fabricated by one‐pot polycondensation. To shorten the relaxation time, dual reversible covalent bonds (disulfide bonds and boronic ester bonds) are incorporated into the HTPB‐based PU networks. Meanwhile, to promote tensile strength, the rigid isocyanate and cross‐link agent are introduced into the networks. Obtained HTPB‐based PU network structures are characterized by FTIR, Raman, and DMA measurements. Obtained HHMB‐4‐20 network shows the best mechanical properties (tensile strength = 6.97 MPa, elongation at break = 302 %), and the mechanical properties almost can be recovered after welding/reprocessing by hot pressing. To satisfy the demands of industrial sustainability, the synthesis of PU networks with capabilities of reprocessing, self‐healing, and welding is a feasible approach.

Self-healing castor oil-based polyurethane networks featuring cyclodextrin–adamantane host–guest interactions

Self-healing castor oil-based polyurethane networks featuring cyclodextrin–adamantane host–guest interactions

Photoinduced Dual Shape Programmability of Covalent Adaptable Networks with Remarkable Mechanical Properties.

As classic shape memory polymers featuring shape reconfiguration of temporary state, covalent adaptable networks containing reversible bonds can enable permanent-state reconfigurability through topological rearrangement via dynamic bond exchange. Yet, such an attractive dual shape programmability is limited by the actuation mode of direct heat transfer and poor mechanical properties, restricting its control precision and functionality. Herein, we presented a method to create nanocomposites with photomodulated dual shape programmability and remarkable mechanical properties leading the fields of covalent adaptable networks. MXene, whose photothermal efficiency was revealed to be regulated by the etching method and delamination, was introduced into polyurethane networks. Upon adjusting the light intensity, the dual shape programmability of both permanent and temporary states could be accomplished, which exhibited potential in information recognition, photowriting paper, etc. Furthermore, owing to the dynamic transcarbamoylation at elevated temperatures, such a phototriggered dual shape programmability could be maintained after the self-healing and reprocessing.

Polybutadiene derived allophanate as the crosslinker for Diels–Alder type self‐healing polyurethane networks

AbstractIntrinsic self‐healing materials have drawn great interest in recent years. The design of novel building blocks is essential for developing polymer networks with different properties. Allophanate is usually regarded as a side product during the preparation of polyurethanes. During the research of self‐healing polyurethane networks, we have studied the terminal functionalization of hydroxyl‐terminated polybutadiene with furfuryl isocyanate and occasionally obtained the furan‐terminated polybutadiene allophanate. The tetra‐branched molecule is employed as the crosslinker in the construction of a series of Diels–Alder type polyurethane networks. These polyurethane networks exhibit good mechanical performance and excellent self‐healing ability. Damages can be healed via the thermo‐promoted dissociation and recombination cycle, giving good to excellent recovery of tensile strength within three cycles of “damage‐repair” processes.

Reasonable stopping method and retracement channel support at fully mechanized top coal caving working face of 15 m extra‐thick coal seam: A case study

AbstractExtra‐thick coal seams are widely distributed in the Datong mine area in China. The rapid stopping of mining and the support withdrawal technology for extra‐thick coal seams need to be developed urgently. The reasonable stopping top coal caving distance, main roof's fracture line position, and large section roadway during the stopping period (LSRSP) support method of the header face of 15 m extra‐thick coal seam are systematically studied by using field measurement, experiment, numerical simulation, and similar material simulation methods. With the increase in stopping coal caving distance, the range of the medium and low displacement zone of the LSRSP overburden gradually expands. In contrast, the depth of the plastic zone decreases. The scope and intensity of the high‐stress area of the overlying rock in front gradually decrease and shift from deep to the outside, while the peak stress area shifts from the top coal area to the coal rib of the retracement channel. Comparing the stopping of medium‐thick and thick coal seam working face, the interaction between “main roof−unmined top coal−supports” is analyzed. The unique characteristics of the extra‐thick coal seam working face are derived: when the stopping coal caving distance is shorter than the length of the key block, the dropped coal body cannot effectively restrict the movement of key blocks. Mutual compression and subsidence occur between key blocks, making the broken coal rock block squeeze into the supports. By the simulation study of each index, the stopping coal caving distance of the extra‐thick coal seam is optimal when it is slightly larger than the length of the key block (i.e., the periodic weighting step), simultaneously, the main roof fracture line behind the supports is most favorable for stopping mining. After ensuring the stability of the LSRSP's overburden structure, the differentiated support scheme of “controlled zoning−strength grading” was proposed, and the scheme was modified and verified by simulating the support prestress field. After field practice, the roof of the retracement channel is better controlled in deformation under the joint horizontal and vertical support, the robust control effect of the combined anchor cable is noticeable, the integrity of the polyurethane network is more substantial, and the working face supports have successfully achieved a safe and rapid evacuation.

Synthesis and characterization of interpenetrating polymer networks (IPNs) based on UV curable resin and blocked isocyanate/polyols

Interpenetrating polymer networks (IPNs) are a non-bonded combination of two or more cross-linked polymers and have superior mechanical properties. Herein we synthesized a series of IPNs by a sequential UV-thermal dual-curing method, which is consisted of UV curable resin network and polyurethanes (PU) network. Blocked isocyanate (BI), polyols, and UV curable resin solutions were mixing completely, the resulting mixture was exposed to UV light to obtain a single network. Then the double network was formed via thermally triggered reaction of deblocking-isocyanate and polyols. The effect of polyol hydroxyl number (from two to six) on properties of IPNs was systematically studied. The results exhibit that pentaerythritol as polyol can be dual-cured by UV and heating to give the highest tensile strength (17.5 MPa), of a 21% increase compared to unheated sample. Furthermore, a series of semi-interpenetrating networks (semi-IPNs) were obtained by using polytetramethylene ether glycol (PTMEG) instead of the polyols. The results showed that introducing interpenetrating or semi-interpenetrating networks exhibit improved mechanical properties of the UV curable resin. Besides, the deblocking temperature of BI is just appropriate for the 3D-printing temperature.

Two-Dimensional Nanosheet-Enhanced Waterborne Polyurethane Eutectogels with Ultrastrength and Superelasticity for Sensitive Strain Sensors.

Sensing materials that are ultrastrong but still superelastic and highly sensitive are crucial for meeting the requirements of future flexible sensors. However, these requirements are challenging to satisfy simultaneously due to the internal constraints among these properties. Here, an ultrastrong and superelastic eutectogel is designed and prepared using a waterborne polyurethane (WPU) network enhanced by two-dimensional (2D) nanosheets in a deep eutectic solvent. The 2D nanosheet-induced noncovalent cross-linking endows the prepared eutectogel with superelasticity and flexibility, and its elongation at break reaches 2071%, higher than those of most polymers (<1000%). Meanwhile, this eutectogel also exhibits a high tensile strength (21.6 MPa), which is strong enough to support 20 000 times its own weight. Such a composite design provides a feasible route for preparing eutectogels with outstanding comprehensive functions without trade-offs among these features. In addition, the eutectogel-assembled sensor possesses a high ionic conductivity of 0.225 S/m and a high strain sensitivity of 1.18 kPa-1. Furthermore, it can be integrated into the sensing arrays for multidimensional signal monitoring without diminishing its pristine strength and flexibility. Surprisingly, the eutectogel can be quickly disintegrated in ethanol due to the WPU's pseudoplastic behavior, providing a competitive way to dispose of waste electronic devices.

Highly Stretchable and Elastic Polymer Electrolytes with High Ionic Conductivity and Li‐Ion Transference Number for High‐Rate Lithium Batteries

Comprehensive SummaryThe ever‐growing demand for wearable electronics drives the development of stretchable lithium‐ion batteries (LIBs) with fast charging capability, in which stretchable polymer electrolytes (PEs) with high ionic conductivity and lithium‐ion transference numbers () are highly desirable. Herein, we report a highly stretchable and elastic PE with high ionic conductivity and , which is applicable in high‐rate and stretchable LIBs. The PE was fabricated by incorporating polyethylene glycol (PEG) and lithium salts into polyurethane networks, wherein α‐cyclodextrin (α‐CD) acts as the cross‐linker. The PEG chains are cross‐linked by covalent and noncovalent bonds, and some PEG chains enter into the cavity of α‐CD to form PEG/α‐CD inclusions. These structural features effectively suppress crystallization of the PEG chains, hinder movement of the counterions of Li+, and endow PE with satisfactory mechanical robustness. The PE with a tensile strength (0.61 MPa) exhibits a large strain at break (840%) and excellent elasticity, possessing a high ionic conductivity (5.0 × 10–4 S·cm–1) and a high (0.52). The Li‖LiFePO4 battery assembled with the PE delivers a high capacity of 75 mAh·g–1 even at the high rate of 16 C. The battery can be stably cycled for 300 and 200 cycles at 1 C and 4 C, respectively.

Thermo-mechanical properties of urethane acrylate networks modulated by RAFT mediated photopolymerization

Reversible addition-fragmentation chain transfer (RAFT) processes in polymer systems have shown great utility in controlling radical polymerizations. Due to the reversible chain transfer mechanism, RAFT agents have been extensively used to synthesize monodisperse linear polymers and block copolymers in solution or emulsion polymerization. On the other hand, little is known about the effects of RAFT agents on the polymerization kinetics and thermo-mechanical properties of cross-linked materials. This work investigates the effect of RAFT agents on photopolymerization behavior and ultimate polymer properties in urethane acrylate systems. Our results indicate that RAFT agent addition has a significantly different impact on network development depending on inherent system characteristics, i.e., systems with glass transition temperature (Tg) below room temperature (LT) or those with Tg above room temperature (HT). When polymerizing with RAFT agents, photopolymerization rate decreases and can be tuned using different concentrations of RAFT agent. The final materials also show increased elongation at break with decreased Young's modulus. However, ultimate thermo-mechanical behavior and mechanical properties are different based on Tg. With RAFT addition decreased Tg is observed from HT polyurethane networks. Tensile toughness is also doubled in comparison to neat HT films. On the other hand, although the Tg of RAFT modified LT polyurethane networks does not change significantly, toughness of the final polymer films varies significantly with RAFT agent concentration. Enhanced toughness is only observed from films with low RAFT agent concentration while toughness decreases with higher loading of RAFT agent. These results demonstrate that the polymer network and thermo-mechanical properties can be modified by introducing RAFT agent which enables dynamic polymer chain rearrangements in both LT- and HT-acrylate network systems.