Polylactic Acid Resin Research Articles

Structural Analysis of Carbon Fiber 3D-Printed Ribs for Small Wind Turbine Blades.

This work provides a structural analysis of small-scale 3D-printed wind turbine ribs subjected to compression. The ribs were manufactured according to NACA 23015 and NACA 633618 geometries, with polylactic acid (PLA) and polylactic acid with carbon fiber additives (CF-PLA). In addition, holes were manufactured into the sample bodies by either 3D printing or drilling for being compared with solid samples. The compression testing was performed by following the ASTM 695D standard, whereas the beginning and propagation of delamination were assessed with the ASTM 5528 standard. Experimental results revealed that 3D-printed built-in holes provided higher compression strength, hence higher structural efficiency, than the drilled samples. Significant improvement by adding carbon fiber additives into the PLA resin system in comparison to raw PLA was detected for at least one of the studied airfoil profiles. NACA geometries also represented a key parameter for avoiding stress concentration areas, as the FEM modeling supported. However, in damaged areas, fracture mechanisms were observed such as bead-bridging, which is a key parameter in reinforcing and consolidating the specimen bodies. Working in better interphase bonding and different additives between beads and layers is highly suggested for future studies.

PLA Renewable Bio Polymer Based Solid-State Gamma Radiation Detector-Dosimeter for Biomedical and Nuclear Industry Applications.

Polylactic acid (PLA) as a "green," renewable corn-soy based polymer resin was assessed as a novel solid-state detector for rapid-turnaround gamma radiation dosimetry in the 1-100 kGy range-of significant interest in biomedical and general nuclear industry applications. Co-60 was used as the source of gamma photons. It was found that PLA resin responds well in terms of rheology and porosity metrics with an absorbed gamma dose (Dg). In this work, rheological changes were ascertained via measuring the differential mass loss ratio (MLR) of irradiated PLA placed within PTFE-framed (40 mm × 20 mm × 0.77 mm) cavities bearing ~0.9 g of PLA resin and pressed for 12-16 min in a controlled force hot press under ~6.6 kN loading and platens heated to 227 °C for the low Dg range: 0-11 kGy; and to 193 °C for the extended Dg range: 11-120 kGy. MLR varied quadratically from 0.05 to ~0.2 (1σ ~ 0.007) in the 0-11 kGy experiments, and from 0.05 to ~0.5 (1σ ~0.01) in the 0-120 kGy experiments. Rheological changes from gamma irradiation were modeled and simultaneously correlated with void-pocket formations, which increase with Dg. A single PLA resin bead (~0.04 g) was compressed 5 min at 216 °C in 0-16 kGy experiments, and compressed 2 min at 232 °C in the 16-110 kGy experiments, to form sturdy ~100 µm thick wafers in the same press. Aggregate coupon porosity was then readily measurable with conventional optical microscope imaging and analyzed with standard image processing; this provided complementary data to MLR. Average porosity vs. dose varied quadratically from ~0 to ~15% in the 0-16 kGy range and from ~0 to ~18% over the 16-114 kGy range. These results provide evidence for utilizing "green"/renewable (under $0.01) PLA resin beads for rapid and accurate (+/-5-10%) gamma dosimetry over a wide 0-120 kGy range, using simple to deploy mass and void measuring techniques using common laboratory equipment.

Experimental Investigation on the Mechanical Properties of Indian Almond Fiber - Reinforced Composites Prepared by Different Types of Resins

ABSTRACT Natural composites are attracted in several engineering applications due to its light weight and environment-friendly nature. This research was intended to investigate the influence of resin type on the mechanical properties of composites. For that, Indian almond fiber-based composites were fabricated using different types of resins and the effect of resin on the mechanical properties of composites was investigated. Totally, three composites such as Polylactic acid (PLA)/Indian almond, Epoxy/Indian almond and Polypropylene (PP)/Indian almond were manufactured by compression molding method. Mechanical properties such as tensile, flexural, impact and hardness were analyzed. Results showed that PLA/Indian almond composite showed the maximum tensile strength of 70 MPa and flexural strength of 117 MPa due to the presence of stiffer PLA resin. PP/Indian almond composite exhibited the higher elongation of 3.83% due to the ductile nature of PP resin. Further, greater impact strength of 5.11 kJ/m2 was noted for PLA/Indian almond composite owing to more energy absorption. Moreover, PLA/Indian almond composite displayed the higher hardness of 90 shore-D. Hence, this research suggests that the PLA resin is better than the epoxy and PP in the improvement of properties of composites. Further, the PLA/Indian almond composite could be used in the structural applications because of its better performance.

Measurement of the structural behaviour of a 3D airless wheel prototype by means of optical non-contact techniques

<p class="Abstract">Additive Manufacturing (AM) is becoming a widely employed technique also in mass production. In this field, compliances with geometry and mechanical performance standards represent a crucial constrain. Since 3D printed products exhibit a mechanical behaviour that is difficult to predict and investigate due to the complex shape and the inaccuracy in reproducing nominal sizes, optical non-contact techniques are an appropriate candidate to solve these issues. In this paper, 2D digital image correlation and thermoelastic stress analysis are combined to map the stress and the strain performance of an airless wheel prototype. The innovative airless wheel samples are 3D-printed by fused deposition modelling and stereolithography in poly-lactic acid and photopolymer resin, respectively. The static mechanical behaviour for different wheel-ground contact configurations is analysed using the aforementioned non-contact techniques. Moreover, the wheel-ground contact pressure is mapped, and a parametric finite element model is developed. The results presented in the paper demonstrate that several factors have great influence on 3D printed airless wheels: a) the type of material used for manufacturing the specimen; b) the correct transfer of the force line (i.e., the loading system); c) the geometric complexity of the lattice structure of the airless wheel. The work confirms the effectiveness of the proposed non-contact measurement procedures for characterizing complex shaped prototypes manufactured using AM.</p>

3D-printed biological habitats for the protection and persistence of <em>Rhizobia</em> species in compacted soils

Microorganisms in soils are responsible for many ecosystem services. However, in degraded soils microbial abundance and function are limited which compromises several biologically facilitated processes. Inoculating soils with desirable microbes can help to re-instate or initiate a viable functioning microbial community. However, establishment success is reliant on the survival of the microorganism in an adverse environment. In this proof-of-concept study, artificial microbial refugia have been developed using resin and light-emitting diode array (LED) 3D printing technology. We assessed whether the artificial refugia, termed a Rhiome, would support better microbial growth in degraded soils. Soil compaction, a form of soil degradation, and Rhizobium, an important microorganism for global agriculture, were both selected as the use case application for this assessment. Different materials together with resin were assessed for their suitability as a 3D printing material and for supporting rhizobial growth. The best result was found in materials constructed with a combination of polylactic acid (PLA) resin, yeast extract and mannitol. In a soil compaction experiment with inoculation of rhizobia, the addition of Rhiome significantly increased bacterium survival in the compacted soil to a level similar to, or higher than, the rhizobial loading in non-compacted soils. Augmentation of the resin with yeast extract and mannitol increased Rhizobium growth significantly compared with the Rhiome constructed only with resin. These results indicate that the Rhiome was highly beneficial for instigating and maintaining significant rhizobia survival and growth in compacted soils. Further work, including near-to-field assessments, are required to assess Rhiome performance in a range of applications and to refine material properties relative to important context-specific performance metrics such as degradation rate. We propose the Rhiome concept as a promising asset in the toolbox for soil ecological restoration as a means of improving soil resiliency.

Effects of Sterilization Methods on Different 3D Printable Materials for Templates of Physician-Modified Aortic Stent Grafts Used in Vascular Surgery-A Preliminary Study.

Three-dimensionally-printed aortic templates are increasingly being used to aid in the modification of stent grafts in the treatment of urgent, complex aortic disorders, often of an emergency nature. The direct contact between the aortic template and the stent graft implies the necessity of complete sterility. Currently, the efficacy of sterilizing aortic templates and the effect of sterilization on the geometry of tubular aortic models are unknown. A complex case of aortic arch dissection was selected to prepare a 3D-printed aortic arch template, which was then manufactured in six popular printing materials: polylactic acid (PLA), nylon, polypropylene (PP), polyethylene terephthalate glycol (PETG), and a rigid and flexible photopolymer resin using fused deposition modeling (FDM) and stereolithography (SLA). The 3D models were contaminated with Geobacillus stearothermophilus broth and Bacillus atrophaeus. The sterilization was performed using three different methods: heat (105 °C and 121 °C), hydrogen peroxide plasma, and ethylene oxide gas. Before and after sterilization, the aortic templates were scanned using computed tomography to detect any changes in their morphology by comparing the dimensions. All sterilization methods were effective in the elimination of microorganisms. Steam sterilization in an autoclave at 121 °C caused significant deformation of the aortic templates made of PLA, PETG, and PP. The other materials had stable geometries, and changes during mesh comparisons were found to be submillimeter. Similarly, plasma, gas, and heat at 105 °C did not change the shapes of aortic templates observed macroscopically and using mesh analysis. All mean geometry differences were smaller than 0.5 mm. All sterilization protocols tested in our study were equally effective in destroying microorganisms; however, differences occurred in the ability to induce 3D object deformation. Sterilization at high temperatures deformed aortic templates composed of PLA, PETG, and PP. This method was suitable for nylon, flexible, and rigid resin-based models. Importantly, plasma and gas sterilization were appropriate for all tested printing materials, including PLA, PETG, PP, nylon, flexible and rigid resins. Moreover, sterilization of all the printed models using our novel protocol for steam autoclaving at 105 °C was also 100% effective, which could represent a significant advantage for health centers, which can therefore use one of the most popular and cheap methods of medical equipment disinfection for the sterilization of 3D models as well.

Automated interlaminar reinforcement with thickness directional fiber arrangement for 3D printing

To improve interlaminar tensile strength, we developed a mechanism to automatically embed carbon fiber reinforced polymer (CFRP) and epoxy resin in the thickness direction by modifying a fused filament fabrication (FFF) 3D printer. To verify how the mechanical properties were improved by embedding continuous carbon fibers, CFRP filaments and epoxy resin were manually embedded into polylactic acid (PLA) resin, and tensile tests were conducted. The results showed that when the fiber volume fraction (Vf) was 6.4%, the tensile strength improved by up to 170% compared to the PLA specimen with 100% filling. To automatically embed the CFRP into the structure, we developed a tube pump as a device to pour the epoxy resin and a mechanism to automatically drop the CFRP into the structure, and attached it to the FFF 3D printer. Based on the tensile tests on the specimens made by automatically embedding CFRP and epoxy resin into the structure, we confirmed an increase in strength of approximately 45%, demonstrating the effectiveness of this method.

Mechanical Properties of Polylactic Acid Resin Composite Filament Reinforced by SUS304 Wire

The purpose of this study is to investigate the mechanical properties of composite filament which made from polylactic acid resin and SUS304 wire for Fused Deposition Modeling. Both of PLA resin and SUS304 wire were supplied to heated extruder for covering the SUS304 wire with melted PLA. The feed rate of both materials was individually controlled by controlling the number of revolutions of stepper motors. In this study, three types of SUS304 wires were used to investigate the effect of surface roughness of wire on the tensile characteristics of composite filament. The surface of SUS304 wire was modified by chemical etching or mechanical grinding to control the surface roughness. For comparing, two modified wires and as received SUS304 wire were used for following experiments. The tensile characteristics of composite filament was investigated by using universal testing machine. Tensile test results showed that the tensile modulus and strength of composite filament was improved compared that of original PLA filament. The pull-out test of composite filament was also revealed that the apparent interfacial shear strength between PLA and SUS304 wire was improved when the surface roughness of SUS304 wire was high. Moreover, when the surface roughness of SUS304 wire was high, the fracture morphology of composite filament was changed.

A three-dimensional (3D) printing approach to fabricate an isolation chip for high throughput in situ cultivation of environmental microbes.

The full plethora of environmental bacteria is often poorly represented in vitro as the majority remain difficult, if not impossible, to culture under standard laboratory settings. These bacteria often require native conditions for the formation of cell masses that collectively have higher chances of survival. With that, a 3D-printed version of the isolation chip (iChip) was used to cultivate bacteria from a tropical peat swamp in situ prior to growth and maintenance in vitro. Briefly, plates made from either acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), or epoxy resin were tested in terms of their usability and durability under acidic conditions similar to those of peat matter. The epoxy resin plates were then found to be most optimal for the sampling conditions. Peat soil samples were collected from the base of a Koompassia malaccensis tree and reconstituted in molten 10% (wt/vol) tryptone soy agar (TSA) prior to inoculation. The iChips were subsequently assembled and buried in the site of origin. As a comparison, bacteria from the same soil sample were cultivated directly on TSA and incubated at 28 °C for two weeks. Thereafter, agar plugs from the iChip were transferred to TSA plates to allow microcolonies within each plug to grow. Each pure isolate from both cultivation approaches that grew was then pooled and extracted for total DNA prior to 16S rRNA gene amplification and sequencing via Illumina MiSeq. Taxonomic abundance comparison revealed that the bacterial taxa at the level of order were significantly different between the two approaches, particularly in the orders, Burkholderiales, Xanthomonodales, Enterobacteriales, and Actinomycetales (differences of 12.0, 7.1, 8.0, and 4.2%, respectively). This indicated that the 3D-printed iChips present a possible low-cost tool for the isolation of bacterial genera that may not be able to grow on media directly in vitro.

Mechanical and medical imaging properties of 3D-printed materials as tissue equivalent materials.

Three materials of polylactic acid (PLA), polyamide 12 (PA12), and light curing resin (LCR) were used to construct phantom using 3D printing technology. The mechanical and medical imaging properties of the three materials, such as elastic modulus, density, effective atomic number, X‐ray attenuation coefficient, computed tomography (CT) number, and acoustic properties, were investigated. The results showed that the elastic modulus for PLA was 1.98 × 103 MPa, for PA12 was 848 MPa, for LCR was 1.18×103 MPa, and that of three materials was close to some bones. In the range of 40∼120 kV, the X‐ray attenuation coefficient of three materials decreased with increasing tube voltage. The CT number for PLA, PA12, and LCR was 144, −88, and 312 Hounsfield units at 120 kV tube voltage, respectively. The density and the effective atomic number product (ρ*Z eff) were computed from three materials and decreased in the order of LCR, PLA, and PA12. The acoustic properties of materials were also studied. The speeds of sound of three materials were similar with those of some soft tissues.

Complex optical properties of polymeric composite materials mixed with quartz powder and investigated by THz time-domain spectroscopy

With the rapid development of terahertz (THz) technology comes the need to further explore the prospects for various applications of THz systems. Due to the strong need, components and equipment involving the exploration are indispensable. In order to find the most suitable material for THz technology, we selected three common materials for different 3D printing techniques—polyamide (PA), polylactic acid (PLA), and light-curable resin. After mixing each material with a quartz powder of a different weight percentage, we observed the change in absorption coefficients and refractive indices of the mixtures by THz time-domain spectroscopy (THz-TDS). The higher the ratio of a quartz powder to a mixture was, the smaller the absorption coefficient of the mixture would be. The optimum rate of change in the absorption coefficient was attained when the weight percentage of a quartz powder in a mixture was 50 wt%. At 1 THz of the measurement of THz-TDS, the average reduction in the absorption coefficients of the three different materials mixed respectively with a 50 wt% quartz powder was 39.17%. Besides reduced absorption coefficients, the mixtures’ refractive indices also changed as the weight percentage of a quartz powder in the mixtures varied. The PLA-based sample mixed with a 50 wt% quartz powder had the highest increase in the refractive index. Mixing quartz powders with materials, therefore, is an effective method to increase refractive indices and decrease absorption coefficients. The method can be applied in 3D printing techniques in the future to enhance the efficiency of THz components manufactured with 3D printing techniques.

Comparative Study on Water Vapour Resistance of Poly(lactic acid) Films Prepared by Blending, Filling and Surface Deposit.

The polylactic acid (PLA) resin Ingeo 4032D was selected as the research object, with a focus on PLA modification by using polymers such as linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE) and ethylene–propylene-diene monomer grafted with glycidyl methacrylate (EPDM-g-GMA), by using fillers such as nano calcium carbonate and zeolite. In order to characterize the deposition effect of Al2O3 on the film surface by plasma-assisted atomic layer deposition, Bio-oriented PLA (BOPLA) with more uniform thickness than blown film was purchased for study. The mechanical properties, friction coefficient, surface contact angle and water vapour transmission rate of the modified PLA film were compared and discussed. The aim was to find out the most influencing factors of film’s water vapour resistance.

Effects of Processing Conditions and Plasticizing-Reinforcing Modification on the Crystallization and Physical Properties of PLA Films.

The polylactic acid (PLA) resin Ingeo 4032D was selected as the research object. Epoxy soybean oil (ESO) and zeolite (3A molecular sieve) were used as plasticizer and reinforcing filler, respectively, for PLA blend modification. The mixture was granulated in an extruder and then blown to obtain films under different conditions to determine the optimum processing temperatures and screw rotation. Then, the thermal behaviour, crystallinity, optical transparency, micro phase structure and physical properties of the film were investigated. The results showed that with increasing zeolite content, the crystallization behaviour of PLA changed, and the haze of the film increased from 5% to 40% compared to the pure PLA film. Zeolite and ESO dispersed in the PLA matrix played a role in toughening and strengthening. The PLA/8 wt% zeolite/3 wt% ESO film had the highest longitudinal tensile strength at 77 MPa. The PLA/2 wt% zeolite/3 wt% ESO film had the highest longitudinal elongation at 13%. The physical properties depended heavily on the dispersion of zeolite and ESO in the matrix.

Design and Analysis of Cng Pressure Vessel Using Natural Fibre Composites

Bio composites comprise one or more phases derived from a biological origin; these may be reinforcements (cotton, hemp, flax, sisal, jute, and kenaf or recycled wood and paper) or organic matrices, for example, polylactic acid (PLA) and soybean resins. Use of natural fibers has been in existence for many generations, however, the discovery and subsequent commercialization of synthetics such as glass, aramids, and carbon fibers in early and mid-twentieth century resulted in the reduced preference for natural fibers in a number of applications. However recent advancement in manufacturing methods and a shift towards environmental protection shifted the focus back to biodegradable composite. This paper deals with the generation of MATLAB script files that assists the user in the design of a biodegradable composite CNG pressure vessel to operate within safe conditions. The inputs of the program are the material properties, ply strength, applied loading, cure and room temperature and fiber orientation. Classical Laminate Analysis (CLA) is a widespread theory in engineering for analyzing the stress/strain behavior of orthotropic laminates under mechanical and hygrothermal loading. CLA is an orthotropic adaptation of Kirchoff’s thin plate theory. The output of the program is extension, coupling and bending stiffness matrices, equivalent elastic constants, thermal, moisture, mechanical and total strain vector, total strains and stresses at ply Interfaces and mid planes. The calculation also predicts the minimum reserve factors with the occurrences of failure at various points in the ply interface.

Electrically conductive and light-weight branched polylactic acid-based carbon nanotube foams

Abstract In spite of the high electrical conductivity of carbon nanotube (CNT), its tendency to aggregate and expensive cost in fabricating aerogel, foams, and porous materials remains a problem. Therefore, we described a simple and feasible way to design light-weight, high electrically conductive, and cost-efficient polylactic acid (PLA)/CNT foams. The branched PLA (BPLA) resin with excellent melt elasticity and foamability was induced by nucleophilic ring-opening reaction of epoxy-based acrylic/styrene copolymer and PLA. After that, BPLA/CNT composites and foams were prepared by melt-mixing and supercritical carbon dioxide foaming technology, respectively. The thermal, electrical, and foaming properties were studied. The resultant BPLA/CNT foam possessed a low density of 0.174 g/cm3 and high crystallinity of 3.03%. An improvement of the oriented structure of CNT induced by cell growth in BPLA matrix increased the conductivity of the foam up to 3.51 × 104 Ω/m. The proposed foaming materials provided a way for designing and preparing high performance CNT products.

Thermal-Assisted Single Point Incremental Forming of Jute Fabric Reinforced Poly(lactic acid) Biocomposites

This paper developed a thermal-assisted single point incremental forming (SPIF) method for biodegradable composite sheets made from jute woven fabric and polylactic acid (PLA) resin. A forming device equipped with a thermal radiation plate was designed for the SPIF of the composite sheets on a three-axis CNC milling machine. A three-tier-plate method in which the composite sheet was sandwiched between an iron plate and an alumina plate was adopted to clamp the composite sheet. The proposed SPIF method was demonstrated on forming of a truncated pyramid part. The effects of clamping method, toolpath, step size and thickness on the formability of the composite were investigated. It was found that the three-tier-plate fixture method was crucial for the successful implementation of the SPIF of the composite. The toolpath had a significant effect on the forming depth. While the surface quality was mainly determined by the step size. The thickness of the composite sheet had a positive effect on is forming depth.

Properties of non-woven polylactic acid fibers prepared by the rotational jet spinning method

The preparation of non-woven polylactic acid (PLA) fibers was carried out by the rotational jet spinning method. The polymers were melted in a heat chamber and centrifuged with a high speed to obtain the fibers with the high productivity. The viscosity of polymers was an important factor for the quality and quantity of the non-woven fiber. In this work, a commercial grade and synthesized PLA were used to prepare the non-woven fiber. The non-woven PLA fibers were produced at different temperatures of 190–230 °C with rotational speed between 650 and 2800 rpm. The morphology of non-woven PLA was investigated by scanning electron microscopy. The effect of temperature was investigated by thermogravimetric analysis (TGA). The non-woven PLA had a smooth surface along the fibers. The result showed that as the temperature or rotational speed increased, the fiber diameter was decreased. The fiber diameters of PLA 3052D, L130, and synthesized PLA (at 650 rpm) decreased to 40%, 40%, and 24%, respectively, when increasing the temperature. The high temperature in the process led to generate the beads. The fiber diameter of PLA 3052D, L130, and synthesized PLA (at 190 °C) decreased to 66%, 23%, and 56%, respectively, with the higher rotational speed. Tonset of TGA showed that the thermal degradation of PLA fibers was reduced compared with PLA resin, but it was still considered to be insignificant after spinning. The wettability of the samples was determined by the mean of the water evaporation. The results showed that the weight of the water in the sample decreased rapidly compared with control cotton, indicating more hydrophobic nature of the fibers obtained at the high rotational speed and temperature.

Evaluating the Electrical Conductivity and Resistivity of Carbon Nanostructures Embedded in the PLA Matrix

In this work, we evaluated the fabrication and three-dimensional printing (3DP) of conductive filaments intended for designing electronic circuits using fused filament fabrication (FFF). For this 15 wt. % of graphene (GR), carbon black (CB) and carbon nanotubes (CNTs) were embedded into thermoplastic polylactic acid (PLA) resin matrix. Measurements of electrical resistance and conductivity, SEM, DSC, and XRD analysis were used to characterize the materials. The resistivity of the polymer nanocomposites was found to be between 0,7 and 1,4 Ω/cm and conductivity ranging between 0,71 and 1,42 S/cm, respectively.

Fabrication of Microneedle from Stretched Biodegradable Polymer Sheet by 3D Laser Machining

Polylactic acid (PLA) microneedles have been usually fabricated by injection molding. Herein, we consider microneedles that mimic the maxillae of mosquito proboscises, which have sharp tips with jagged harpoon-like protrusions. In case of such microneedles, filling the melting PLA resin up to the tip of the mold trough without burrs is challenging. To address this issue, we have proposed a new microneedle fabrication method in this paper. In this method, the needle with the desired shape was obtained from a PLA sheet by femtosecond laser machining. The needle was turned by 90°, and its tip further cut obliquely with the laser for three-dimensional (3D) sharpening. Tensile and buckling tests were conducted by using a test piece cut out from the PLA sheet. It was experimentally established that the strength and Young’s modulus along the sheet’s stretch direction are higher than those along its perpendicular direction. The 3D sharpened PLA microneedle successfully penetrated an artificial skin made of polydimethylsiloxane. A pair of microneedles were alternately vibrated against each other, mimicking the motion of mosquito two maxillae. With this alternate vibration, the resistance force during insertion was found to be lower compared to that without vibration.

Interfacial modified unidirectional wheat straw/polylactic acid composites

Among the agricultural crops, wheat is one of the most important and broadly planted food crops. However, abundant wheat straw resources were used to incinerate, which was a great waste of fiber resources, and meanwhile caused great pollution to the ecological environment. In this work, a simple hot compress method that used intact wheat straw with different volume fractions (20% and 30%) as a filler to reinforce the polylactic acid resin was explored to prepare a biodegradable composite by thermal compression method. Initially, the compressed wheat straw exhibited excellent tensile strength (96.86 MPa), even higher than intact wheat straw (92.18 MPa). The surface modification treatment was carried out with 2% and 4% concentrations of sodium hydroxide (NaOH). Then the tensile and bending strength of the modified wheat straw/polylactic acid composites were 32.41 MPa and 78.52 MPa, which were 22.16% and 22.44% higher than those of the untreated composites. The scanning electron microscopy images of the surface of modified wheat straw and fractured composite cross section revealed significantly rougher surface morphology and stronger interfacial bonding with the matrix. This work demonstrated the feasibility and good mechanical property of the composites reinforced with intact wheat straw by simple hot compression method, which provided a possible strategy to utilize the straw materials for multiple applications.