Impact Strength Properties Research Articles

Preparation and Application of Radiation-crosslinked Polypropylene by One-step Process for Corrosion Prevention of High-temperature Pipelines

Using propylene-ethylene block copolymer (PPB) and metallocene polypropylene random (mPPR) as matrix, olefin block copolymer (OBC) and metallocene polyethylene (mPE) as reinforcement, trimethylolpropane trimethacrylate as sensitizer, antioxidant 1010 and dioctadecyl 3,3-Thio-dipropionate as antioxidant, the radiation-crosslinked polypropylene with excellent high-temperature performance was prepared by one-step process and it was used to produce the heat shrinkable tape with three layers structure further. The effect of the formula, the orientation, the crosslinking, the heat treatment and shrink on the crosslinked-polypropylene were studied. The results show that the crosslinked-polypropylene has optimum overall property when the amounts of PPB, mPPR, OBC, and mPE were 50, 10, 15, and 15 phr, respectively. After the orientation in one-step process and the radiation crosslinking with the irradiation dose of 6 Mrad, the tensile strength, the elongation at break, the shrinkage ration, the gel content of the crosslinked-polypropylene reached 33 MPa, 390%, 30%, 51%, respectively. After heat treatment, its mechanical properties further improved and the decrease of its tensile strength and elongation at break did not exceed 15% after thermal ageing at 130 oC for 100 days. Moreover, the corresponding heat shrinkable tapes show outstanding peel strength, impact strength and cathodic disbondment properties in various conditions.

Analysis of existing studies on wood under impact and ballistic loads

Wood is one of the oldest building materials. However, with the advent of the industrial revolution, metal and reinforced concrete structures have almost completely displaced wood from the market of basic building materials. At the same time, wood is widely used in the manufacture of furniture, decoration, floors, auxiliary structures, etc., and this applies to all spheres of human life and everyday life. A separate niche is occupied by wood asa material for fortifications, as the most accessible. Studies of the ballistic characteristics of wood are most relevant in forensics, due to the fact that bulletsfired in urban conditions very often hit wooden objects [1].The war unleashed by the Russian Federation in Ukraine forces engineers to look for the most rational materials for the construction of buildings forboth civilian and military purposes. And in this case, wood can be a competitive material along with concrete and steel, given the fairly good ability of woodto absorb energy. Certain types of wood are considered impact-resistant, so beech is used for the manufacture of hammer heads [3]. In addition to solidwood, there are quite a large number of wood-based materials, such as: glued wood, cross-laminated timber, glued veneer lumber and many others.These materials are already widely used in the construction of both low-rise and multi-story buildings. The properties of these materials for the perceptionof vertical and horizontal loads have been actively studied since the 1960s. However, the characteristics of impact strength and ballistic properties ofthese materials have hardly been studied. This paper considers the state of modern research on the ballistic properties of wood and materials based on it with the prospect of further research and use in engineering protection structures.

Microstructural Characterization of Cellulose Nanocrystals and Microcellulose from Bamboo (Bambusa longispatha) for Reinforcing Ordinary Portland Cement Matrix.

This study investigates the microstructural characterization of cellulose nanocrystals (CNC) and microcellulose (MC) extracted from bamboo fibers (Bambusa longispatha) and their potential as reinforcement agents in ordinary Portland cement (OPC) composites. CNC with a mean particle size of 29.3 nm and MC with a mean size of 14.6 × 103 nm were incorporated into OPC at varying concentrations (0.1%, 0.2%, 0.4%, and 0.6% by cement mass). The compressive strength analysis revealed that increasing MC content led to a decrease in strength, with reductions ranging from 8.8% to 25.9% relative to the control OPC, while the CNC-enhanced composite at 0.4% achieved the highest compressive strength of 43.2 MPa. Flexural strength analysis indicated a minor increase in strength with MC addition (from 7.5 MPa to 8.1 MPa), while CNC addition at 0.1% improved flexural strength to 8.2 MPa but declined with higher concentrations. SEM and stereo microscopy demonstrated MC and CNC dispersion and highlighted microstructural differences, including pore distribution in the composites. XRD analysis showed increased crystallinity for CNC composites compared to pure OPC, with the highest crystallinity index of 52.2% observed at 0.4% CNC. This study highlights that CNC at specific concentrations can enhance OPC mechanical properties, while higher MC and CNC additions may impact strength properties variably due to their microstructural integration and crystallinity. These findings support the potential for bamboo-derived cellulose materials in enhancing cementitious composite performance.

Influence of Coir Fibre Preparation on Mechanical Properties of Coir Fibre/Epoxy Resin Composites

Polymer composites have been utilized across various industries, especially in transportation, for many years. With a growing emphasis on sustainable production resources, the industry increasingly favours composite materials reinforced with natural fibres or particles. Unlike conventional fibres such as glass, carbon, or aramid, natural fibres typically have low compatibility with polymer matrices, often necessitating pretreatment to enhance bonding. In this study, coir fibres were physically and chemically treated with sodium bicarbonate solutions at varying concentrations (5–15%) and immersion durations (0–5 days). The treated fibres were then mixed into epoxy resin and poured into moulds to produce test specimens for evaluating mechanical properties. The fibre content in the composites ranged from 10 to 20%. Statistical analysis revealed that immersion time significantly affects all mechanical properties tested (tensile modulus, tensile strength, strain, and impact strength). Solution concentration significantly influences tensile modulus and strain, while fibre content significantly affects tensile modulus and strength. The conducted optimization shows that the best mechanical properties are achieved with the minimum tested coir fibre content of 10%. Maximum stiffness and strength can be expected with the longest immersion time of 5 days in the highest solution concentration of 15%. The best strain and impact strength properties, however, are observed at the lowest solution concentration of 5%.

Turning Discarded Agricultural Remnants and Poultry Waste into Usable Hybrid Polymer Matrix Reinforcements: An Experimental Study

The primary objective of the present study was to transform discarded agricultural remnants and poultry waste into value-added materials. Rice straw and chicken feathers are disposed of after their primary consumption into landfills or are incinerated, causing pollution and environmental threats. In this study, epoxy composites were fabricated using different volume proportions (5–45%) of these raw and alkali-treated remnants, and their mechanical strength was tested. The flexural strength of the rice straw composites and chicken feather composites initially decreased with the addition of fibers from 5 to 35 vol% and then the values increased when the fiber content was more than 35 vol%. The chicken feather composites showed increased impact strength with fiber addition. Alkali treatment of the rice straw resulted in improved flexural and impact strengths of the composites due to the removal of the waxy layer on the fiber surface, which was observed in the FTIR studies. Alkali treatment of the chicken feathers did not produce any significant change in the flexural strength of the composites, but their impact strength increased with fiber addition. Hybrid composites fabricated using rice straw and chicken feathers exhibited enhanced flexural and impact strength properties both with and without the alkali treatment, corroborating the synergistic effect of these fibers. SEM analysis of the fractured samples showed noteworthy interfacial adhesion between the fibers and matrix. This study presents a better method for converting these disposable materials into value-added usable materials and increasing their life cycle in the circular economy.

Multi-objective optimization of micro crystalline cellulose and montmorillonite filled poly lactic acid bio–composite and its characterizations

In this research study, the synthesis of poly lactic acid (PLA) based bio composite material factors contributions were investigated through the Taguchi-based grey relational analysis (GRA) technique. Effects of micro crystalline cellulose (MCC) and montmorillonite (MTT) nano clay filler, sorbitol (S) plasticizer, and temperature (T) operating factor on the PLA matrix through melt-mixing preparation method. The tensile strength (TS), Young modulus (YM), flexural strength (FS), flexural modulus (FM), hardness, impact strength (IS), water absorption (WA), and density properties of bio composite material were investigated for each experimental setup (orthogonal array, L16). Additionally, neat PLA and optimal sample structural, thermal, and morphological properties were examined through Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (X-RD), thermal gravimetry analysis/differential thermal gravimetry (TGA/DTG), and DSC and SEM analyses. The obtained result for optimal mechanical and physical properties of MCC/MTT/S/PLA bio composite was MCC at level 3 (6%), MTT at level 4 (9%), S at level 2 (10%), and T at level 4 (175 °C). Analysis of variance (ANOVA) shows that MTT has the greatest significant effect on mechanical and physical properties of MCC/MTT/S/PLA bio composite followed by MCC, T, and S. The confirmation test indicates that the improvement of weighted grey relational grade (GRG) from 0.7896 to 0.846 and the FTIR, XRD, thermal gravimetry/differential scanning calorimetry (TG/DSC), and scanning electron microscopy (SEM) results indicates that the good interaction between PLA and fillers, improvement of thermal and morphological properties of optimal (6MCC/9MTT/10S/175 °C) bio composite samples. Therefore, the multi-response characteristics of MCC/MTT/S/PLA bio composite can be highly improved by this technique.

EVALUATION OF PROPERTIES OF WOOD PLASTIC COMPOSITES MADE FROM SEVEN TYPES OF LIGNOCELLULOSIC FIBERS

This article aims to investigate the characteristics of wood plastic composites (WPC) prepared from polyethylene (PE) reinforced with lignocellulosic fibers derived from the xylem and bark of Masson pine, fir, cypress, as well as from Moso bamboo. The surface polarity and elemental composition of fibers were determined through contact angle measurements and X-ray photoelectron spectroscopy (XPS). The lignocellulosic fiber/PE composites were manufactured through hot-pressing technique, and their water absorption, mechanical properties, and mildew resistance were evaluated. The results revealed that the surface free energy of xylem fibers was higher than that of bark fibers among the three conifer species. XPS analysis showed that the O/C ratio of bark was consistently lower than that of xylem fiber. Among the three conifers, the Masson pine bark had the lowest O/C ratio (22.25%), while its xylem fibers had the highest ratio of 41.64%. WPC made with bark fibers had better water resistance. Additionally, the composites reinforced with xylem fibers showed superior static bending strength, impact strength, and mildew-resistant properties as compared to the composites reinforced with bark fibers. WPC made from bamboo fibers exhibited the best water resistance, with a water absorption rate and thickness swelling rate of 1.83% and 1.42%, respectively. They also had the highest static bending strength, elastic modulus, and impact strength, at 41.31 MPa, 3.82 GPa, and 10.24 kJ/m2, respectively. The WPC made from fir xylem fibers showed the most effective mildew resistance, with the smallest damage (0.50).

Synergistic Reinforcement with SEBS-g-MAH for Enhanced Thermal Stability and Processability in GO/rGO-Filled PC/ABS Composites.

The integration of compatibilisers with thermoplastics has revolutionised the field of polymer composites, enhancing their mechanical, thermal, and rheological properties. This study investigates the synergistic effects of incorporating SEBS-g-MAH on the mechanical, thermal, and rheological properties of polycarbonate/acrylonitrile-butadiene-styrene/graphene oxide (PC/ABS/GO) (PAGO) and the properties of polycarbonate/acrylonitrile-butadiene-styrene/graphene oxide (PC/ABS/rGO) (PArGO) composites through the melt blending method. The synergistic effects on thermal stability and processability were analysed by using thermogravimetry (TGA), melt flow index (MFI), and Fourier-transform infrared spectroscopy (FTIR). The addition of SEBS-g-MAH improved the elongation at break (EB) of PAGO and PArGO up to 33% and 73%, respectively, compared to the uncompatibilised composites. The impact strength of PAGO was synergistically enhanced by 75% with the incorporation of 5 phr SEBS-g-MAH. A thermal analysis revealed that SEBS-g-MAH improved the thermal stability of the composites, with an increase in the degradation temperature (T80%) of up to 17% for PAGO at 1 phr SEBS-g-MAH loading. The compatibilising effect of SEBS-g-MAH was confirmed by FTIR analysis, which indicated interactions between the maleic anhydride groups and the PC/ABS matrix and GO/rGO fillers. The rheological measurements showed that the incorporation of SEBS-g-MAH enhanced the melt flowability (MFI) of the composites, with a maximum increase of 38% observed for PC/ABS. These results demonstrate the potential of SEBS-g-MAH as a compatibiliser for improving the unnotched impact strength (mechanical), thermal, and rheological properties of PC/ABS/GO and PC/ABS/rGO composites, achieving a synergistic effect.

Optimization of UV-Curable Polyurethane Acrylate Coatings with Hexagonal Boron Nitride (hBN) for Improved Mechanical and Adhesive Properties.

Polymer coatings are widely used in industries for protection, decoration, and specific applications, typically including volatile organic compounds (VOCs) to achieve low viscosity. The growing environmental concerns and the anticipated limits on fossil feedstock have driven the coating industry towards eco-friendly alternatives, with UV-curing technology emerging as a promising solution due to its energy efficiency, low-temperature operation, reduced VOC emissions, and high curing speed. Polyurethane acrylates (PUAs) are critical in UV-curable formulations, offering excellent flexibility, impact strength, optical, and adhesion properties. However, UV-cured PUA coatings face limitations in thermal stability and tensile strength, which can be addressed by incorporating fillers. This study investigates the effects of multi-functionalized hexagonal boron nitride (hBN) nanoparticles on the mechanical, thermal, optical, and adhesion properties of UV-cured PUA films and coatings for pre-coated metals. The results demonstrated that incorporating hBN nanoparticles enhanced the mechanical and thermal properties of the nanocomposite films, with optimal performance observed at 0.5% hBN loading. Despite the improved properties, the FTIR spectra indicated that the low concentration of hBN did not produce significant changes, potentially due to the overshadowing signals from the difunctional polyurethane acrylate.

Impact Strength Properties and Failure Mode Classification of Concrete U-Shaped Specimen Retrofitted with Polyurethane Grout Using Machine Learning Algorithms

The inherent brittle behavior of cementitious composite is considered one of its weaknesses in structural applications. This study evaluated the impact strength and failure modes of composite U-shaped normal concrete (NC) specimens strengthened with polyurethane grout material (NC-PUG) subjected to repeated drop-weight impact loads (USDWIT). The experimental dataset was used to train and test three machine learning (ML) algorithms, namely decision tree (DT), Naïve Ba yes (NB), and K-nearest neighbors (KNN), to predict the three failure modes exhibited by U-shaped specimens during testing. The uncertainty of the failure modes under different uncertainty degrees was analyzed using Monte Carlo simulation (MCS). The results indicate that the retrofitting effect of polyurethane grout significantly improved the impact strength of concrete. During testing, U-shaped specimens demonstrated three major failure patterns, which included mid-section crack (MC), crushing foot (CF), and bend section crack (BC). The prediction models predicted the three types of failure modes with an accuracy greater than 95%. Moreover, the KNN model predicted the failure modes with 3.1% higher accuracy than the DT and NB models, and the accuracy, precision, and recall of the KNN model have converged within 300 runs of Monte Carlo simulation under different uncertainties.

Effect of conductive carbon black on the lightning strikes resistance of carbon fiber-reinforced epoxy resin

The effect of conductive carbon black (0.5 wt%) on the properties of carbon fiber-reinforced epoxy resin (Rockwell hardness, Charpy impact strength, tensile and flexural properties, electrical conductivity, and resistance to lightning discharges) was investigated. The composites were obtained by the infusion method. A slight decrease in flexural modulus was observed, while the hardness and Young's modulus increased. The resistivity decreased four times. Simulated multiple lightning discharges confirmed the better electrical conductivity of the composite with the addition of conductive carbon black, which resulted in five times decrease in the laminate damage area.

Development and characterization of polymer composites with cotton straw fiber derived from agricultural wastes

AbstractIn the global pursuit of using sustainable component materials, reinforcement materials derived from agricultural straw waste have attracted widespread attention to develop polymer composites. However, the polar and hydrophilic properties of straw fibers limit their interfacial adhesion behavior, which leads to poor physico‐mechanical and tribological properties of the resulting polymer composites. In this work, cotton straw fibers (CSFs) were derived from agricultural cotton straw wastes, and then were treated with sodium hydroxide solutions of different concentrations (0–7 wt.%). Physical and mechanical properties were analyzed and tribological properties of the developed CSF reinforced polymer composites were investigated systematically. The experiment results indicated that the incorporation of treated‐CSFs in the polymer composite had less effect on the density, whereas it significantly enhanced the water absorption, impact strength and tribological properties. The worn surface morphology analysis revealed that the addition of the treated‐CSFs is conducive to the formation of the contact plateaus, which is in turn beneficial in improving the wear resistance of the treated‐CSF reinforced polymer composites. Overall, the developed polymer composites reinforced with the treated‐CSFs have shown better physico‐mechanical and tribological properties. The present work confirms the possibility of using agricultural corn straw waste as reinforcement fibers, and then paves the path for the development of future commercial plant fiber reinforced polymer composites.Highlights The usability of cotton straw waste as a reinforcement in polymer composite was investigated. The physico‐mechanical and tribological properties of the polymer composites were evaluated. The alkali‐treated cotton straw fibres were more effective in improving the impact resistance and tribological properties. Use of cotton straw waste in the polymer composite reduced its impact on the environment.

Influence of varying matrix/fiber concentration on mechanical properties of bi-directional carbon fiber reinforced polymer composite

The polymer composites comprising bi-directional carbon fabric incorporated in the epoxy matrix have been developed for various advanced applications in the field of automobile and aerospace sectors. The distinct advantages of using epoxy material with hardener are good adhesion, high tensile, compression and bending strengths, good corrosion, and heat resistance properties. Using carbon fiber enhances the stiffness, reduces the weight, and improves the chemical resistance apart from possessing high thermal conductivity and low coefficient of thermal expansion. Considering all the above aspects, the present work proposes to investigate the mechanical properties of carbon-reinforced epoxy composites with fiber matrix ratios of 40:60, 50:50, and 60:40 by wt% as these particular combinations have been limitedly addressed so far. The well-known hand lay-up technique has produced the laminates and the test samples prepared from the laminate are subjected to tensile, flexural, hardness, and impact strength properties. Based on the experimental work of the composites made in the laboratory, the fiber matrix ratio of 60:40 has revealed the best attributes in terms of higher mechanical strengths compared to the composites with fiber matrix ratio of 40:60 and 50:50 and the data obtained have been substantiated using scanning electron microscope analysis.

Bond Strength Assessment of Normal Strength Concrete-Ultra-High-Performance Fiber Reinforced Concrete Using Repeated Drop-Weight Impact Test: Experimental and Machine Learning Technique.

Ultra-high-performance concrete (UHPC) has been used in building joints due to its increased strength, crack resistance, and durability, serving as a repair material. However, efficient repair depends on whether the interfacial substrate can provide adequate bond strength under various loading scenarios. The objective of this study is to investigate the bonding behavior of composite U-shaped normal strength concrete-ultra-high-performance fiber reinforced concrete (NSC-UHPFRC) specimens using multiple drop-weight impact testing techniques. The composite interface was treated using grooving (Gst), natural fracture (Nst), and smoothing (Sst) techniques. Ensemble machine learning (ML) algorithms comprising XGBoost and CatBoost, support vector machine (SVM), and generalized linear machine (GLM) were employed to train and test the simulation dataset to forecast the impact failure strength (N2) composite U-shaped NSC-UHPFRC specimen. The results indicate that the reference NSC samples had the highest impact strength and surface treatment played a substantial role in ensuring the adequate bond strength of NSC-UHPFRC. NSC-UHPFRC-Nst can provide sufficient bond strength at the interface, resulting in a monolithic structure that can resist repeated drop-weight impact loads. NSC-UHPFRC-Sst and NSC-UHPFRC-Gst exhibit significant reductions in impact strength properties. The ensemble ML correctly predicts the failure strength of the NSC-UHPFRC composite. The XGBoost ensemble model gave coefficient of determination (R2) values of approximately 0.99 and 0.9643 at the training and testing stages. The highest predictions were obtained using the GLM model, with an R2 value of 0.9805 at the testing stage.

Development and Characterization of Hybrid Particulate-fiber Reinforced Epoxy Composites

Although considered wastes, animal fibers and gastropod shell particles are biodegradable, have low density, high stiffness, considerably high impact absorption capacity and relatively low cost. Therefore, they are finding increasing use as reinforcement materials in polymer composites. This research work studied the tensile, hardness, and wear resistance properties of hybrid snail shell (SSP) and chicken feather barb fibers (CFB) reinforced epoxy composites. The stir cast molding technique was utilized to synthesize the composite samples with 3, 6, 9, 12, 15, and 18 wt.% of the hybrid SSPs/CFB. Compared with the control samples, SSP/CFB hybrid reinforcements enhanced the mechanical properties of the composites. Composites with intermediate weight fraction of 9 wt.% SSP/CFB exhibited overall optimum properties when benchmarked against the control sample with approximately 37, 37, 133, 19, and 59% improvement in wear, hardness, impact, and ultimate tensile strength properties respectively. These enhancements suggested a synergistic effect of the two reinforcement phases. The results presented in this study demonstrated the potential of utilizing bio-derived waste materials for synthesizing eco-friendly composites.

Studying The Effect of Gamma Rays on The Impact Strength and Wear Properties of Silicon Carbide SIC and Graphite Gr Nanocomposites

Studying The Effect of Gamma Rays on The Impact Strength and Wear Properties of Silicon Carbide SIC and Graphite Gr Nanocomposites

Influence of Extrusion Screw Speed and CNT Concentration on the Mechanical and EMI Properties of PC/ABS Based Nanocomposites.

This study investigates the effect of extrusion screw speed and carbon nanotube (CNT) concentration on the thermal, mechanical, and electromagnetic interference shielding effectiveness (EMI SE) properties of Polycarbonate (PC)/acrylonitrile-butadiene-styrene (ABS) and its polymer nanocomposites (PNCs) by means of design of experiments (DoE) approach. A masterbatch method was employed to obtain the best dispersion of the CNTs throughout the polymer matrix. This study evaluates the thermo-mechanical characterisation of the polymers and PNCs at varying screw speeds to assess filler matrix bonding. The results highlight that CNT concentration has a significant effect on all mechanical properties, while screw speed only affects the Charpy impact strength and flexural properties of the samples. Compounding at 200 rpm has the best flexural and tensile strength, which is attributed to the best filler matrix bonding (highest storage modulus) of the PNCs. The best EMI SE results were obtained at 10 wt.% CNTs. This research contributes valuable insights into the effect of CNT concentration and extrusion screw speed on the mechanical, thermal and EMI SE properties of PC/ABS and its PNCs.

The use of thermoplastic polyurethane composites to develop a model of the renal pelvicalyceal system by 3D printing

Composites based on thermoplastic polyurethanes (TPUR) were obtained using the twin-screw extrusion method. Influence of the addition of 6, 7 and 8 wt% silica and 1–3 wt%. aluminum oxide and 1–3 wt%. dibutyl phthalate (plasticizer) on Rockwell hardness, Charpy impact strength and tensile mechanical properties was tested. The best properties were obtained for a composite containing 8 wt% silica, 3 wt% aluminum oxide and 3 wt% dibutyl phthalates. For this composite, the renal pelvicalyceal system was obtained using the FFF method.

Static and dynamic mechanical characterization and thermal analysis for multi‐ply structure of woven nettle (Girardinia diversifolia) reinforced poly(lactic acid) biocomposites

AbstractPoly(lactic acid) fiberwebs and multi‐ply assemblies of nettle woven reinforcement are used to develop a series of nettle/PLA biocomposites with different reinforcement orientations. The tensile strength, flexural strength, impact strength, and thermal properties of the biocomposites are found to improve by piling nettle fabrics and are also found to depend strongly on the piling architecture and the test direction. It is possible to obtain a biocomposite with higher degrees of isotropy and enhanced mechanical properties by using cross‐ply laminates. The three‐layered woven fabric reinforced PLA biocomposite with a reinforcement orientation 0°/45°/90° shows the best results among all the biocomposites developed in this study. The tensile strength, Young's (tensile) modulus, flexural strength, impact strength, storage modulus, and loss modulus of the biocomposite are found as 55.25 MPa, 6.30 GPa, 85.83 MPa, 63.74 J/m2, 10.08 GPa, and 0.75 GPa, respectively. In this biocomposite, a fair adhesion between matrix and reinforcement is noticed, and this is justified by retardation of crack propagation as well as by substantial energy dissipation. The thermal stability of the biocomposite does not get effected much, but the percent crystallinity increases by 25.84%. The degradation kinetics and the activation energy of the biocomposite are determined through a differential fitting of Arrhenius model. The soil burial test reveals 15.06% of weight loss and 50.56% strength loss for this biocomposite just after 20 days of burial under soil.Highlights Multi‐ply architecture of woven fabric reinforcement in nettle/PLA biocomposites. Nearly isotropic biocomposite through angle‐ply orientation of reinforcement. Biocomposite with remarkable static and dynamic mechanical properties. Augmented kinetic parameters through model fitting of Arrhenius equation. Biocomposite with excellent thermo‐recyclability and biodegradability.

Preparation and properties of hybrid specific length carbon fiber thermoplastic composites by suspension method

AbstractCarbon fiber reinforced thermoplastic composites have such advantages as low density, high strength, high temperature resistance, impact resistance, and good ductility, but due to the density difference between carbon fibers and resin fibers, it is difficult to mix them uniformly. Hence, it is difficult to prepare the composites with the uniform properties. In order to solve this problem, a preparation process based on solid phase mixing of carbon and resin fibers by suspension method is proposed in this paper. The carbon fiber reinforced thermoplastic composites (CFRTPs) can be prepared by dispersing carbon fibers of a certain length (~50 mm) and resin fibers in suspension through ultrasound‐assisted and churn‐combing methods. The effects of carbon fiber length, content and molding process on the mechanical properties of the CFRTPs were studied. The results show that the carbon fiber content and length are the main factors affecting the mechanical properties as well as void ratio of CFRTP. The performance of composites is significantly improved with the increase of carbon fiber length. While the length of carbon fiber is 50 mm and the content is 30 wt%, the prepared CFRTP has the best performance, with the tensile strength of 182.1 MPa, the bending strength of 354.3 MPa, the impact strength of 67.2 KJ·m−2, and the material void ratio of 0.65%. The study shows that the suspension method is feasible for the preparation of the CFRTPs. It is beneficial to improve production efficiency and decrease cost of production for the CFRTPs.Highlights Carbon fiber reinforced thermoplastic composites can be prepared by dispersing carbon fibers of a certain length (~50 mm) and resin fibers in suspension through ultrasound‐assisted and churn‐combing methods. Through the cooling‐high pressure molding process, the porosity of CFRTP is reduced and the mechanical properties of CFRTP are improved. The tensile strength, bending strength, and notch‐free impact strength properties of CFRTP are best when the carbon fiber content is 30% and the CF length is 50 mm. The method is characterized by simple process, low cost and high mechanical properties.