Maleic Polypropylene Research Articles

Covalent Adaptable Network of Semicrystalline Polyolefin Blend with Triple-Shape Memory Effect

A covalent adaptable network (CAN) of semicrystalline polyolefin blends with triple-shape memory effects was fabricated by the reactive melt blending of maleated polypropylene (mPP) and maleated polyolefin elastomer (mPOE) (50 wt/50 wt) in the presence of a small amount of a tetrafunctional thiol (PETMP) and 1,5,7-triazabicyclo [4,4,0]dec-5-ene (TBD). The polymer blend formed a chemically crosslinked network via the reaction between the thiol group of PETMP and maleic anhydride of both polymers in the blend, which was confirmed by FTIR, the variation of torque during the melt mixing process, a solubility test, and DMA. DSC analysis revealed that the crosslinked polyolefin blends show two distinct crystalline melting transitions corresponding to each component polymer. Improved tensile strength as well as elongation at break were observed in the crosslinked blend as compared to the simple blend, and the mechanical properties were maintained after repeated melt processing. These results suggest that thermoplastic polyolefin blends can be transformed into a high-performance and value-added material with good recyclability and reprocessability.

Upgrading properties and circularity of the recycled flexible polypropylene by developing composites with an optimal combination of a fumed silica and maleated polypropylene copolymer: Influence of the addition of copolymer, type of fumed silica and the silica/copolymer ratio on packaging properties

Rigid polypropylene is mechanically recycled but flexible polypropylene is mostly used in energetic valorization because of the poor properties of the recycled polymer. A recycled polypropylene-based composite with outstanding properties for flexible food packaging was developed. For the first time, the influence of maleated polypropylene copolymer addition and the fumed silica/copolymer ratio on the packaging properties of recycled flexible polypropylene under the effects of silica hydrophilicity was investigated. The structural, morphological, thermal, mechanical, melt flow, overall migration, water vapor barrier and sealing properties of the developed nanocomposites were analyzed. Prominently, the addition of 1:1 maleated polypropylene and hydrophobic nanosilica improved the global performance of all tested methods. The recycled polypropylene had an overall migration to olive oil of 17 mg dm−2, exceeding the limit allowed for food packaging, but the developed added-value composite reduced it to the tolerance limit according EU legislation. The seal strength was drastically increased by 50 % with adhesive peeling, high thermal stability, and well-dispersed particles without affecting the ductility.

Zinc oxide as a new catalyst for poly(lactic acid)/maleated polypropylene reactive blending: an approach to enhance miscibility and mechanical properties

Zinc oxide as a new catalyst for poly(lactic acid)/maleated polypropylene reactive blending: an approach to enhance miscibility and mechanical properties

Enhancing poly(lactic acid)/maleated polypropylene blend with magnesium oxide catalyst: a reactive blending approach for improved mechanical properties

Some defects of polylactic acid (PLA), especially its poor mechanical properties, were modified using a minimum content of non-biodegradable maleated polypropylene (MAPP). To this end, first, the amount of MAPP was optimized, which was 20 wt.%. Second, MgO was used as a new catalyst to improve the exchange reactions between active groups in both polymers in a reactive blending process. Tensile and izod analyses showed that, compared to neat PLA, with a slight decrease in modulus and tensile strength, elongation at break, and impact resistance were improved in the presence of 20 and 0.1 wt.% of MAPP and MgO, respectively. This improvement in mechanical properties can be related to the exchange reactions between two polymers and the formation of PLA-MAPP block copolymers. MFI and WDCA analyses demonstrated the increase in melt flowability and surface hydrophilicity of the resulting blends, respectively. DSC analysis showed that the Tg values of both polymers approached each other in the presence of catalyst. Also, the elimination of cold crystallization of PLA and the decrease in the Tm and crystallinity of both polymers are clear reasons for the miscibility of the alloy. TEM displayed the proper dispersion of MgO nanoparticles within the polymer matrix, and in addition, the XRD test also proved the decrease in the crystallinity of both polymers and appropriate miscibility of the samples containing 20 and 0.1 wt.% of MAPP and MgO, respectively. These results can promise the design of a compound with the maximum amount of PLA for further use in various industries.

Investigation of the Effect of Coupling Agent on the Properties of Kenaf Fiber/Polypropylene Composites

In a competitive product market, manufacturers ought to utilize eco-friendly materials to reduce the environmental impact of their products. Kenaf (Hibiscus cannabinus) is an annual plant that produces bast fiber and develops rapidly. These fibers have excellent properties and could serve as ideal reinforcing fillers for wood-based products. This study aims to investigate Maleated Polypropylene (MAPP) as a coupling agent for Kenaf fiber (KF)/Polypropylene(PP) composite. Three distinct composites were created using the following ratios: Sample 1 (Kenaf 20g: PP 180g), Sample 2 (Kenaf 10g: PP 180g: MAPP 10g), and Sample 3 (Kenaf 15g: PP 180g: MAPP 5g). All materials are mixed and extruded in a single-screw extruder at 185 to 200 °C at 50 rpm. A granulator is then utilized to palletize the samples. For testing, tensile and impact testing is conducted for mechanical properties, water absorption for physical properties, and Scanning Electron Microscopy (SEM) for morphological characterization. The thermal characteristics of the composites are analyzed using thermogravimetric analysis (TGA). The results indicate that the KF/PP composite with a coupling agent has a higher tensile strength with a value of 29.3 MPa compared to the KF/PP composite without a coupling agent with a value of 22.4 MPa. Water absorption of composite with coupling agent was also less than without coupling agent with a value of 1.05% and 1.31% respectively.

Using furniture factory waste sawdust in wood-plastic composite production and prototype sample production

This study investigated the possibility of furniture factory waste sawdust (FFWS) utilization in polypropylene (PP) composites and producing furniture support leg prototypes. Test samples were manufactured using a single screw extruder and injection molding machine utilizing 10, 15, 20, 25, 30, and 35% by weight of FFWS and 0% or 3% maleated polypropylene (MAPP). Selected mechanical and physical properties of manufactured samples were determined. The presence of FFWS and MAPP significantly improved mechanical properties compared to neat PP. The higher FFWS amount increased the flexural strength, flexural modulus, tensile modulus, impact resistance, and density. Tensile strength and elongation at break decreased with filler amount, but the addition of MAPP caused a dramatic increase in tensile strength. In addition, flexural strength, flexural modulus, tensile strength, elasticity modulus, and density values of the composites containing MAPP had higher values than the ones without MAPP. However, impact resistance and elongation at break values were slightly decreased with the addition of MAPP. Optimization results showed that formulation mixtures containing 20% filler and 3% MAPP fit best for prototype furniture legs manufacturing.

Recycling of Nonwoven Waste Resulting from the Manufacturing Process of Hemp Fiber-Reinforced Recycled Polypropylene Composites for Upholstered Furniture Products

Waste recycling is a solution that reduces the environmental impact of waste landfilling or incineration. The aim of this paper is to investigate both the effect of incorporating recycled fibers obtained by defibrating 50/50 hemp/rPP nonwoven waste and the effect of the compatibilizer on the properties of composite materials. Composites incorporating 50% and 100% recycled fibers were treated with 2.5% and 5% maleated polypropylene (MAPP), respectively, and compared to both the untreated composites and the composite obtained by thermoforming from the nonwovens that generated the waste. The incorporation of 50% and 100% recycled fibers into composites decreased the tensile strength by 17.1–22.6%, the elongation at break by 12.4–20.1%, the flexural strength by 6.6–9%, and flexural modulus by 10.3–37%. The addition of 5% MAPP showed the greatest improvements in mechanical properties of composites containing 100% recycled fibers, as follows: 19.2% increase in tensile strength, 3.8% increase in flexural strength, and 14.8% increase in flexural modulus. Thermal analysis established that at temperatures ranging between 20 °C and 120 °C, the composites were thermally stable. SEM analysis revealed good coverage of the reinforcing fibers, and EDX analysis confirmed the presence of the compatibilizing agent in the structure of the composite material.

Converting flax processing waste into value added biocomposites

Flax fibers have excellent strength and other properties preferable for textile, composites and other applications. In addition to being an important industrial crop, many studies have been reported on the use of flax fibers, flax fabrics and other flax based products as reinforcement for composites. Processing flax fibers into yarns generates considerable (up to 25%) amounts of fibrous and non-fibrous waste which is generally discarded or used for low value applications. Pure flax fiber have current selling price between 6.5 and 7 Euro/kg compared to 0.16–0.19 Euro/kg for the flax waste used in this study which could make the composites highly affordable. To realize the unique properties of flax fibers such as its relatively high strength and add value to the waste, flax processing waste were used as reinforcement for polypropylene (PP) composites. Flax waste was separated into fibrous and non-fibrous (powder) components and combined in various ratios with poly(propylene) as the matrix. A compatibilizer (maleated polypropylene) (MAPP) was used to improve the surface interaction and adhesion between reinforcement and matrix and enhance the properties. Substantial increase in strength and modulus were observed due to the addition of the compatibilizer. A compatibilizer content of 3% was found to be optimum when the tensile strength was highest at 27 MPa and tensile modulus was 1212 MPa. The thermal conductivity and noise insulation properties also showed an improvement from 0.050 to 0.039 W/mK and 0.05–0.35 respectively after the addition of the compatibilizer. Flax-PP composites have properties surpassing that of commercially available medium density particle boards and that of neat PP.

Development of natural fiber reinforced thermoplastic bonded hybrid wood veneer composite

This study aimed at preparing thermoplastic based hybrid wood veneer composite panels in which bamboo fiber reinforced thermoplastic (BPC) was used in granular form as one component and Melia dubia wood veneers as the second component. BPC was prepared using twin screw extruder and maleated polyethylene/ maleated polypropylene as a coupling agent. The effect of polymer type i.e., polypropylene (PP), high density polyethylene (HDPE) and poly butylene adipate-co-terephthalate (PBAT) and bamboo fiber content (10%, 30%, and 50%) on physical, mechanical and thermal properties of Melia dubia plywood has been investigated. Plywood prepared with BPC exhibited superior mechanical properties as compared to pure polymer irrespective of polymer type. The improvement in flexural strength at 30% bamboo content was 14.6%, 17.6% and 38% for PP, HDPE and PBAT based BPC, respectively. Volumetric swelling in panels on water absorption was not influenced by the presence of bamboo fibers in the polymer. The improvement in mechanical properties of BPC bonded plywood was due to manifestation of an improved interfacial adhesion between BPC and wood veneers via coupling agent. SEM images revealed pertinent bonding between BPC and wood veneers in the form of mechanical interlocking.

Complex Effects of Hemp Fibers and Impact Modifiers in Multiphase Polypropylene Systems

Natural fibers-reinforced polymer composites have progressed rapidly due to their undeniable advantages. Most of the commercial polypropylene (PP)-based materials are characterized by either high impact toughness or high stiffness, while the manufacture of PP composites with both good toughness and stiffness is challenging at present. In this work, poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) and poly(styrene-b-butadiene-b-styrene) (SBS) copolymers were used in different amounts as modifiers in PP/hemp fibers (HF) composites, with the aim to use them for electrical vehicle parts. The interface in these multiphase systems was controlled by the addition of maleated polypropylene (MAPP). SEBS and SBS showed different effects on the elongation at break of the blends and the corresponding composites due to the HF that stiffened the multiphase systems. Similarly, a different action of MAPP was observed in the composites containing SEBS or SBS: higher Young's and storage moduli were obtained for the composite containing SBS, while greater elongation at break and impact strength values were recorded for the SEBS-containing system. In addition, a remarkable dispersion in the MAPP-containing composite and two times smaller average particle size were revealed by the SEM analysis for the SEBS particles compared to the SBS ones. The higher affinity of SEBS for PP compared to that for SBS and the different morphological characteristics of the systems containing SEBS and SBS may explain the different effects of these impact modifiers on the mechanical properties of the composites. The composites developed in this work were designed as substitutes for the fully synthetic polymeric materials or metal components used in the manufacturing of automotive parts.

Investigation of Jute/Tetracarpidium conophorum reinforced polypropylene composites for automobile application: Mechanical, wear and flow properties

Recent interest in using natural fibers as fillers in various composite materials has sparked the desire of researchers and manufacturing businesses to develop natural fiber composites that may be used as alternative, cheap, sustainable and ecoefficient materials in automobiles. In that respect, the present study was tailored towards harnessing the attractive properties of jute fiber and Tetracarpidium conophorum (African walnut shell particulate) along with thermoplastic “polypropylene”, to develop composite materials with improved properties which can be adopted in automobiles. Alkaline treated African walnut shell particulate (AWSP) and jute fiber were added to polypropylene at a proportion of 2–8 wt% and 5–30 wt% respectively in the presence of 2 wt% maleated polypropylene. Samples were developed at 170 °C and 0.25 kPa pressure, and their mechanical, wear and flow properties were assessed. The result revealed that an improvement of 51.98 %, 42.26 %, 55.23 %, 30.95 %, 54.36 % for flexural strength, tensile strength, impact strength, compressive strength, and hardness respectively. However, a reduction of 380. 48 % and 78.98 % were observed for wear loss and melt flow. The Taguchi Optimization revealed that 2 wt% AWSP and 20 wt% jute fiber addition gave the optimum mechanical performance. The research proved that the hybridization of jute fiber and AWSP resulted in improved polypropylene composites which can be adopted for automobile applications.

Chemical, Thermal and Mechanical Characterization of Licorice Root, Willow, Holm Oak, and Palm Leaf Waste Incorporated into Maleated Polypropylene (MAPP).

The effect of four lignocellulosic waste fillers on the thermal and mechanical properties of biocomposites was investigated. Powdered licorice root, palm leaf, holm oak and willow fillers were melt compounded with polypropylene at two different weight contents, i.e., 10 and 30, and then injection molded. A commercially available maleated coupling agent was used to improve the filler/matrix interfacial adhesion at 5 wt.%. Composites were subjected to chemical (FTIR-ATR), thermal (TGA, DSC, DMA) and mechanical (tensile, bending and Charpy impact) analyses coupled with a morphological investigation by scanning electron microscopy. Although similarities among the different formulations were noted, holm oak fillers provided the best combination of thermal and mechanical performance. In particular, at 30 wt.% content with coupling agent, this composite formulation displayed remarkable increases in tensile strength and modulus, flexural strength and modulus, of 28% and 110%, 58% and 111%, compared to neat PP, respectively. The results imply that all these lignocellulosic waste fillers can be used successfully as raw materials for biocomposites, with properties comparable to those featured by other natural fillers.

Analysis of Polymeric Composites of Phormium Tenax

Phormium tenax is a vegetal fiber with a mechanical strength of 711 ± 61.1 MPa, which is higher than the range of sisal (468-640MPa) and similar to the well-known curauá fiber (913 MPa). In this study, Phormium tenax composites coated with maleated polypropylene in a polypropylene matrix were prepared with 20%, 30%, and 35wt% of fibers, with and without aluminum sheets made from beverage cans. Some samples were made by extrusion and compression molding process, and others only through compression molding. In addition, density tests indicated lightness in composites of Phormium tenax. Samples were submitted to thermal analyzes, X-ray diffraction, Fourier Transform with Infrared Region, and scanning electron microscopy. Their fibers content of cellulose, hemicellulose, lignin, ashes,and total extractives are respectively 44.27%, 13.20%, 15.02%, 23.4%, and 4.11%. Some based-PP composites reinforced with Phormium tenax showed improvement in the flexural strength, such as based-PP reinforced with long and continuous fibers, with a flexural strength of 64.94 MPa, and 52,30 MPa, respectively. It was concluded that tensile strength in PP-based composites reinforced with Phormium tenax could be enhanced with some adjustments in the material processing.

Cross-Linking of Polypropylene via the Diels-Alder Reaction.

In this work, the possibility of preparing cross-linked polypropylene (PP) via Diels–Alder (DA) chemistry is explored. The overall strategy involves reaction of maleated polypropylene (the starting material), furfuryl amine (FFA), and bismaleimide (BM) as the cross-linking agent. The occurrence of reversible cross-linking was studied by checking the presence of relevant peaks in FTIR spectra, i.e., CH out-of-plane bending vibrations of the furan ring’s peak (γCH) at an absorption band of 730–734 cm−1, CH=CH of the BM aromatic ring’s stretching vibrations (υCH=CH) at an absorption band of 1510 cm−1, and the DA adduct (C-O-C, δDAring) at an absorption band of 1186 cm−1. In agreement with the spectroscopic characterization, the presence of a cross-linked network is also confirmed by rheology, namely the higher storage modulus (G′) compared with loss modulus (G″) value (G′ >> G″), as obtained via temperature sweep. Both the maleic anhydride (MA) content as well as the annealing temperature (50 °C and 120 °C) favor the DA reaction, while only partial de-cross-linking (retro DA) is observed at the higher temperature range of 150–200 °C. In addition, the products show higher mechanical robustness and thermal stability compared to the starting material.

Simulated Recycling of Polypropylene and Maleated Polypropylene for the Fabrication of Highly-Filled Wood Plastic Composites

In this study, polypropylene [PP] and maleic anhydride grafted polypropylene [MAPP] were reprocessed from one to three times to simulate recycling. 30 wt % of the reprocessed PP and MAPP were compounded with 70 wt % wood filler to fabricate highly filled wood plastic composites [WPCs]. The neat and composite samples were produced using a batch mixer and injection molder. The effect of recycling and maleation of PP was analyzed using light scattering, nuclear magnetic resonance, rheology, microscopy, and other physical/mechanical properties. While thermomechanical processing may lead to chain scission reactions, shown by a reduction in melt viscosity and weight-average molecular weight, the observed changes are minor and did not change the bulk properties significantly. The repeated reprocessing allowed for the incorporation of up to 70 wt % wood flour [WF] to fabricate the highly filled WPC while the maleation allowed for better interactions and the composite’s strength. Overall, the WPCs with maleic anhydride displayed appealing physical properties due to their increased tensile properties and a lack of oxidation or significant level of degradation. This indicates that the maleation of reprocessed PP could be an important and effective strategy to reduce virgin and petroleum-based MAPP while revitalizing mechanical properties for WPCs.

The Integral Utilization of Date Palm Waste to Produce Plastic Composites.

In this work, date palm waste (DPW) stemming from the annual pruning of date palm was used as a reinforcing filler in polypropylene matrix at 20–60 wt.%. Only a grinding process of the DPW has been performed to ensure no residue generation and full utilization. The present work investigates how the DPW use affects mechanical properties and water absorption of the ensuing composite. The effect of the addition of maleated polypropylene (MAPP) as a coupling agent on the composite properties was also studied. It was shown that the reinforcing potential of DPW was strongly dependent on aspect ratio and interface quality. The MAPP addition resulted in a composite with higher strength and stiffness than the neat PP, meaning that DPW behaves as reinforcement. The difference in the reinforcing effect was explained by the change in the quality of the interface between date palm waste and the polypropylene polymeric chain.

Online Pre-Treatment of Thermomechanical Pulp with Emulsified Maleated Polypropylene for Processing of Extruded Thermoplastic Composites

The effectiveness of maleated polypropylene (MAPP) in emulsified form for the pre-treatment of thermo-mechanical pulp (TMP) before extrusion with polypropylene fibres was evaluated. MAPP in pellet form, which was applied during the compounding step, served as a benchmark. In addition, commercial softwood flour was included as a reference. The influence of the temperature during the defibration process and the presence or absence of the coupling agent on composite performance were evaluated. Composites were processed with a high wood content of 70 wt.%, which is common for extruded profiles. It was found that TMP based on Robinia (Robinia pseudoacacia L.) conferred higher strength properties to the composites compared to TMP based on Scots pine (Pinus sylvestris L.), which was attributed to the higher length/diameter ratio of fibres in Robinia. However, under the conditions of this study, strength properties were superior and water uptake and swelling were reduced when wood flour was used instead of TMP. On the other hand, in many formulations, larger improvements in flexural and tensile strength due to MAPP were found for the TMP-based composites compared to the wood flour-based composites. This could be due to the larger surface/volume ratio for TMP compared to wood flour and more efficient stress transfer from fibres to the matrix. Results from X-ray photoelectron spectroscopy (XPS) showed that TMP surfaces were more hydrophobic than wood flour due to coverage with lignin, which reduced the effectiveness of MAPP. Esterification between the emulsified MAPP and fibre surfaces was determined using Fourier-Transform Infrared (FTIR) spectroscopy, but some non-activated maleic anhydride remained. Under the conditions of this study, MAPP added during compounding provided better performance compared to MAPP which included a non-ionic emulsifier and which was added during the refining process. Lower temperature (150 °C) during defibration was shown to be beneficial for the strength properties of composites compared to high temperature (180 °C) when MAPP was included in the formulations.

Influence of Alkali Treatment and Maleated Polypropylene (MAPP) Compatibilizer on the Dry‐Sliding Wear and Frictional Behavior of Borassus Fruit Fine Fiber (BFF)/Polypropylene (PP) Polymer Composites for Various Engineering Applications

Tribological properties of the novel Borassus fruit fine fiber‐ (BFF‐) reinforced polypropylene (PP) composites with respect to fiber matrix surface modifications have been described. Composites were fabricated by an injection molding process using Borassus fruit fine fiber (BFF) of 5 wt.% as reinforcement and polypropylene (PP) as a matrix component. Fibers were treated with alkali (T) to remove the residual lignin (if present) and to enhance the interfacial adhesion between the fiber/matrix interface. Alkali treatment reveals additional reactive functional groups here on the surface of the Borassus fiber, allowing effective interaction bonding with the polypropylene matrix. Borassus fibers are primarily treated with an alkali solution to extract weaker unstructured amorphous constituents so that the fibers retain crystallized components, thereby strengthening the fiber’s strength. A 5 wt.% of maleated polypropylene (MAPP) was used as a compatibilizer to improve the interfacial adhesion between fiber and the polymer matrix. The wear and frictional behavior of BFF/PP composites with respect to the modifications were evaluated by steel counterface utilizing pin‐on‐disc test contraption under dry‐sliding conditions. The sliding velocity, applied load, and sliding distance were maintained as 2.198 m/s, 9.81–29.43 N, and 4000 m, respectively. The results demonstrate that the reinforcement of BFF to polypropylene matrix and the modifications improved the wear properties of the neat polymer matrix. Findings concluded that the abrasive wear resistance of T + PP + MAPP composite showed better interfacial adhesion and bonding, thus resulting in better tribological performance as compared to the other three compositions under different loading conditions. The effective substantial improvement of the coefficient of friction has been observed in alkali‐treated fiber and polypropylene matrix with MAPP compatibilizer (T + PP + MAPP) composites due to the presence of MAPP compatibilizer and alkali‐treated fibers. The frictional coefficient of T + PP + MAPP possesses better interfacial bonding strength upon NaOH treatment, and coupling agent, which results in enhancement of effective contact surface area and good surface friction characteristics, has been observed under different loading conditions. The fracture mechanism of worn‐out portions of BFF/PP composites was studied using high‐resolution scanning electron microscopy to analyze various imperfections like debonding, splits, fiber cracks, and wreckage or fragments formation.

The effect of natural modifiers for starch hydrophobization on performance of composite based on ethylene acrylic acid copolymer

AbstractAs a renewable resource, starch is considered to be fully biodegradable and nonpolluting to the environment but the hygroscopicity of starch is the main disadvantage for wider applicability in the production of a polymer‐based material. Hydrophobically modified starch prepared using natural‐based plasticizers/modifiers in a first step ([−]‐diisopropyl D‐tartrate [DiPT], ricinoleic acid [RA] and epoxidized soybean oil [ESO]), and maleated polypropylene (MAPP) in a second step contributed to better compatibility, and thus reinforcing of composites. Tailored processing conditions, structural/morphological properties, hydrophobicity, and water‐resistance of the modified starch were established. In addition, the Charpy impact and tensile strength of composites, based on poly(ethylene‐co‐acrylic acid) (EAA) and modified starches, were determined. Increased tensile strength and Young modulus of the composite using starch‐modified with DiPT‐MAPP, that is, 3 and 83%, respectively, indicated the possible applicability of obtained materials.

Use of a bis(aminoalkyl)‐calix[4]arene derivative as cross‐linking agent to enhance functional and mechanical properties of a maleated polypropylene

AbstractAn isotactic polypropylene grafted by 1 wt% of maleic anhydride (iPP‐g‐MAH) was chemically modified to provide it with new functional abilities and improved mechanical properties. The specific additive considered in this work is a derivative of bis(aminoalkyl)‐calix[4]arene. Not only this molecule serves as a cross‐linking agent, but it offers grafting sites for metallic ions that confer electrolytic conductivity to the initially insulating polyolefin. Materials were synthesized by reactive extrusion, and subsequently manufactured as plates by injection molding. The three‐dimensional macromolecular architecture was optimized by adjusting the NH2:MAH molar ratio in a range from 0.5:1 to 1:1. Fourier transform infrared spectroscopy revealed the amine/ anhydride chemical reactions, while gel content measurements were used to determine the degree of cross‐linking. The crystalline microstructure of the different materials was characterized by two complementary methods: (a) overall crystallinity by differential scanning calorimetry; (b) lamellar thickness by thermal fractionation using the self‐successive auto‐nucleation procedure. Only a small decrease of the crystalline lamellae is observed. The mechanical properties were determined by a video‐controlled tensile testing method and by Brillouin spectroscopy. A transition from brittle to ductile behavior was observed for increasing cross‐links density. Scanning electron microscopy on fracture surfaces showed that ductile fracture was favored by the development of fibrils.