Nucleating Agent For Crystallization Research Articles

Synergistic effect of TiO2 nanoparticles and poly (ethylene-co-vinyl acetate) on the morphology and crystallization behavior of polylactic acid

The impact of adding ethylene vinyl acetate copolymer (EVA 80) and 1 wt% TiO2 nanoparticles on the morphology and crystallization behavior of poly(lactic acid) blends was investigated using DSC, SEM, and POM. Thermal analysis revealed the enhancement of crystallinity of PLA in the presence of TiO2 and higher EVA 80 content in the blend. The PLA and EVA 80 components showed compatibility, as evidenced by the shift of the glass transition temperatures of the PLA phase in the blend to lower values compared to neat PLA. The lower temperature shift of the cold crystallization of the PLA and the formation of the small spherulites of the PLA in the blends indicated that the EVA 80 and TiO2 act as a nucleating agent for crystallization. The non-isothermal crystallization parameters of the composites were evaluated using Avrami's modified model, the MO approach, and Friedman’s isoconversional method. The Avrami’s modified rate constant (K) and the effective activation energy values significantly increased with the incorporation of EVA 80 and TiO2 nanoparticles. Furthermore, the thermogravimetric analysis (TGA) showed improved thermal stability of PLA by adding EVA 80 and TiO2.

Forefront Research of Foaming Strategies on Biodegradable Polymers and Their Composites by Thermal or Melt-Based Processing Technologies: Advances and Perspectives.

The last few decades have witnessed significant advances in the development of polymeric-based foam materials. These materials find several practical applications in our daily lives due to their characteristic properties such as low density, thermal insulation, and porosity, which are important in packaging, in building construction, and in biomedical applications, respectively. The first foams with practical applications used polymeric materials of petrochemical origin. However, due to growing environmental concerns, considerable efforts have been made to replace some of these materials with biodegradable polymers. Foam processing has evolved greatly in recent years due to improvements in existing techniques, such as the use of supercritical fluids in extrusion foaming and foam injection moulding, as well as the advent or adaptation of existing techniques to produce foams, as in the case of the combination between additive manufacturing and foam technology. The use of supercritical CO2 is especially advantageous in the production of porous structures for biomedical applications, as CO2 is chemically inert and non-toxic; in addition, it allows for an easy tailoring of the pore structure through processing conditions. Biodegradable polymeric materials, despite their enormous advantages over petroleum-based materials, present some difficulties regarding their potential use in foaming, such as poor melt strength, slow crystallization rate, poor processability, low service temperature, low toughness, and high brittleness, which limits their field of application. Several strategies were developed to improve the melt strength, including the change in monomer composition and the use of chemical modifiers and chain extenders to extend the chain length or create a branched molecular structure, to increase the molecular weight and the viscosity of the polymer. The use of additives or fillers is also commonly used, as fillers can improve crystallization kinetics by acting as crystal-nucleating agents. Alternatively, biodegradable polymers can be blended with other biodegradable polymers to combine certain properties and to counteract certain limitations. This work therefore aims to provide the latest advances regarding the foaming of biodegradable polymers. It covers the main foaming techniques and their advances and reviews the uses of biodegradable polymers in foaming, focusing on the chemical changes of polymers that improve their foaming ability. Finally, the challenges as well as the main opportunities presented reinforce the market potential of the biodegradable polymer foam materials.

Heterogeneous nucleation of polyethylene crystals on binary hexagonal nanoplatelets

Crystal nucleating agents offer an effective strategy for controlling the morphology, dimensional stability and rate of solidification of polymers during processing. Molecular dynamics (MD) simulation can shed light on nucleation behavior at the nanoscopic length and time scales over which nucleation occurs. In this work, crystal nucleation of a polyethylene oligomer, n-pentacontane, on three graphene-like substrates, hexagonal boron nitride (hBN), molybdenum disulfide (MoS2), and tungsten disulfide (WS2), was simulated, and the thermodynamic efficiencies of these substrates as nucleating agents were determined. Experimental measurements of heterogeneous nucleation of a high-density polyethylene on nanoparticles of these three graphene-like materials were performed using the method of dispersed microdroplets in an immiscible polystyrene matrix. Qualitative agreement between simulations and experiments was observed for trends in nucleation rate, J, and interfacial free energy difference, Δσ, with JhBN>JMoS2>JWS2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$J_{\ ext{hBN}} > J_{\ ext{MoS}_{2}} > J_{\ ext{WS}_{2}}$$\\end{document}. The simulations are then used to gain additional insight into the mechanisms of nucleation. Epitaxy is confirmed in all systems, with small mismatches in lattice spacing being accommodated by strain in the oligomer crystal. However, epitaxy alone is insufficient to explain the observed trends. The strength of interaction between the nucleating agent and the polyethylene oligomer is found to be the strongest predictor of nucleating agent efficiency. The strength of interaction is in turn related to the density of interaction sites at the interface: hBN has the highest density, and thus the fastest nucleation rate.

Regulating cell morphology of poly (lactic acid) foams from microcellular to nanocellular by crystal nucleating agent

The inherent shortcomings of poor melt strength and crystallization behavior constrain the foamability and mechanical properties of poly (lactic acid) (PLA). In this work, a crystal nucleating agent was introduced into PLA system to solve the aforementioned issues by manipulating crystallization process. Isothermal crystallization results implied that the crystal nucleating agent promoted PLA crystallization greatly, where the adjusted ranges of crystallization rate and crystallinity were expanded obviously. Results indicated that the modified PLA foams displayed a mixed distribution of nanoscale and microscale cells at low temperatures, while the uniform pentagonal shape cells emerged in the foams prepared at 112 ℃. Accordingly, the cell size decreased from 44.62 μm to 360 nm, and the cell density increased from 9.06×108 cells/cm3 to 7.48×1013 cells/cm3. Moreover, the compressive strength of the modified foams was enhanced notably than that of pure PLA foams. Overall, the crystallization and foaming properties of PLA were analyzed systematically, the foaming properties were improved significantly by controlling proper crystallization, and this work would provide a prospective strategy to fabricate high performance PLA foams with controllable cell structures and high compression properties.

Cellulose nanocrystals enabled sustainable polycaprolactone based shape memory polyurethane bionanocomposites

In recent years, shape memory polyurethanes have gained substantial attention and are targeted for a range of smart and functional materials. In this work, the development of nanocrystalline celluloses (CNCs) enabled polycaprolactone-based shape memory polyurethane biocomposite using an in situ one-pot reactions is reported. The incorporation of up to 10 wt% CNCs resulted in a remarkable enhancement in the tensile strength at yield (from 0.2 MPa to 7.2 MPa), tensile strength at break (167% improvement), and modulus of elasticity (from 3.5 to 139.3 MPa) while maintaining the elongation at break. This was attributed to the simultaneous action of CNCs as a nucleating agent for crystallization and highly compatibilized reinforcing agent of the network. Moreover, the in situ incorporation of CNCs enhanced the shape memory capability of polyurethanes, which enables its employment in functional material applications, such as the biomedical sector. The intimate interfacial adhesion between the CNCs and the polymer matrix, which promoted shape fixating and recovery, was confirmed by fractured surface morphology studies. Rheology characterizations provided strong evidence that the addition of CNCs increased the shape fixity attributed to the stiffness of CNCs below the glass transition temperature (Tg) compared to the neat PU in conjuncture with the higher Tg of CNCs. Overall, the developed polymer nanocomposites are appealing materials for biomedical applications.

Influence of fibrillated poly(tetrafluoroethylene) on microcellular foaming of polyamide 6 in the presence of supercriticalCO2

AbstractIn this article, PA6/poly(tetrafluoroethylene) (PTFE) composites were prepared by internal mixer with high rotor speed. The existence of PTFE nano‐fibrillation network structure was observed by scanning electron microscopy (SEM) analysis. The effect of PTFE on crystallization and rheological behavior of PA6 was evaluated. The result showed that the PTFE fibrils improved the crystallization properties of PA6 and do not change the crystal structure. The PTFE effectively enhanced the melt strength of PA6 by fibrillation. The PA6/PTFE composites were then foamed assisted by supercritical CO2. The PTFE was used as cell nucleating agent, crystal nucleating agent and melt strength enhancement agent in the foaming process. Finally, the microcellular PA6 foams were successfully obtained with the cell density higher than 109 cells/cm3, the cell size of ca. 14 μm and the volume expansion ratio of 16.

Effect of Neutralizer on Transparency of Nucleating Agent-Containing Polypropylene

The effects of neutralizer species on the transparency of injection-molded plates were studied using isotactic polypropylene (PP) containing a crystal nucleating agent—i.e., 1,3:2,4-bis-o-(4-methylbenzylidene)-d-sorbitol (MDBS). A plate containing lithium stearate (StLi) was more transparent than one containing calcium stearate (StCa) when the MDBS content was 0.1 wt. %. The addition of StLi accelerated the formation of MDBS fibers and the crystallization of PP. However, when the MDBS content was 1.0 wt. %, StCa improved the transparency more effectively than StLi. These results indicate that the combination of an appropriate amount of MDBS and the correct neutralizer species is critical for enhancing the transparency of injection-molded PP plates.

Synergetic effect of crystal nucleating agent and melt self-enhancement of isotactic polypropylene on its rheological and microcellular foaming properties

Crystal nucleating agent Bis (3, 4- dimethylbenzylidene) sorbitol (DMDBS) was used to tune the melt strength and microcellular foaming properties of isotactic polypropylene (iPP) in this study. Rheological testing results reveal that the introduction of DMDBS could enhance the storage modulus and complex viscosity of iPP, obviously increase its crystallization onset temperature, compared to its counterparts without DMDBS. The addition of DMDBS could also significantly increase the cell nucleating ability of iPP, due to its large surface, cooperating with a thermal history control treatment. Quite fine microcellular iPP/DMDBS foams were fabricated with relatively small average cell sizes of nano to several micrometers, and cell densities up to 1011∼1012cells/cm3, using the synergy effect of DMDBS and iPP’s melt self-enhancement. Under a comparatively low re-saturation pressure of 8 to 12 MPa, ideal microcellular foams could be generated, at a temperature zone of 158 to 162°C, which is slightly below to iPP’s original pellets nominal melting point.

Enhancing gas barrier performance of polylactic acid/lignin composite films through cooperative effect of compatibilization and nucleation

AbstractIn this work, lignin was used as a heterogeneous nucleating agent to increase polylactic acid (PLA) crystallinity. To enhance the gas barrier performance of PLA/LG composite films, two graft copolymers, polylactide‐graft‐glycidyl methacrylate (PLA‐g‐GMA) and polylactide‐graft‐poly (ethylene glycol) methyl ether methacrylate (PLA‐g‐PEGMA) were successfully synthesized and separately used as compatibilizers to modify PLA/LG composite properties such as interfacial adhesion, crystallinity, and mechanical properties. Since crystallites can act as obstacles to gas diffusion, the higher the crystallinity of the polymer matrix, the better gas barrier performance of the composite film will be. The crystallinity and crystalline structure of the PLA matrix was demonstrated by wide‐angle X‐ray diffraction and differential scanning calorimetry results. Since LG particles can act as efficient heterogeneous crystal nucleating agents, a roughly 50% reduction in oxygen permeability (PO2) was obtained by adding 1 phr LG to the PLA matrix (PLA/1LG). Following addition of 10 phr PLA‐g‐GMA to the PLA/LG composite, PLA/PLA‐g‐GMA/LG composite films showed lower gas barrier properties than PLA/LG composites without added compatibilizer. Moreover, the interfacial adhesion of PLA/LG composites was significantly improved after addition of PLA‐g‐GMA. Therefore, PLA/PLA‐g‐GMA/3LG showed the highest tensile strength, 33% higher than that of neat PLA. Following addition of 10 phr PLA‐g‐PEGMA to the PLA/LG composite, the long liner side chains of PLA‐g‐PEGMA were able to act as nucleating agents for PLA to promote the crystallization of PLA. Accordingly, PLA/PLA‐g‐PEGMA/3LG with 3 phr LG showed a roughly 86% reduction in PO2 when compared with neat PLA film.

The mechanism of the crystalline characteristics of spinel-induced epitaxial growth of diopside in CMAS glass-ceramics

The edge-to-edge matching model (E2EM) is used to predict and analyze the epitaxial growth mechanism of spinel and diopside in CaO-MgO-Al2O3-SiO2 (CMAS) glass-ceramics. At the same time, the prepared glass-ceramics were characterized by X-ray diffraction (XRD) and electron backscatter diffraction (EBSD). It is found that the theoretically predicted phase interface where epitaxial growth can occur is consistent with the conclusion measured by characterization. In the crystallization zone: <1-12 >spinel//<001>diopside (1-11-)spinel at an angle 1.06° (200)diopside, <1-12 >spinel//<101>diopside (311)spinel at an angle 1.26° (1- 31)diopside. Through models and experiments, it was found that spinel with a lattice constant of 7.632–8.597 Å (Fd-3 m) can provide a special nucleation interface for diopside, which can effectively induce the precipitation of diopside. This study provides good theoretical guidance for the preparation of diopside. Meanwhile, the model has strong potential to be used to develop new crystal nucleating agents in glass-ceramics.

Microstructure, mechanical and electrical characterizations of bimodal and nanocellular polypropylene/graphene nanoplatelet composite foams

In this work, linear and branched polypropylene (PP)/ graphene nanoplatelet (GnP) composite foams were prepared using supercritical CO2. The morphology of nanocomposite foams was imaged on SEM. Branched PP foams revealed bimodal cellular morphology, while linear PP exposed nanocellular structures. The effect of cell modality and adding GnP on the mechanical and electrical properties of nanocomposite foams were investigated. Addition of GnP to linear PP decreased cell density and made cell distribution uniform due to its functionality of crystal nucleating agent While in branched PP foams, it was seen by the dynamic observation that GnP acted as bubble nucleating agent, resulting in a fine cell size and increasing the foam density. Nanocellular foams exhibited better mechanical properties than bimodal but the limited expansion ratio. However, some bimodal foams presented comparable mechanical properties to non-foamed samples, in spite of high expansion ratio. Addition of graphene nanoplatelet to some extent improved the specific tensile modulus and strength of foams. The electrical conductivity of composites was reduced by foaming. However, this reduction was very significant in the case of bimodal foams.

Ultra-lightweight, super thermal-insulation and strong PP/CNT microcellular foams

The global energy crisis has been widely concerned by the public due to the massive energy requirement caused by rapid-developing economy and society. Ultra-lightweight, super-insulating, and strong polymer foams exhibit a promising prospect, in terms of saving materials and resources, and reducing energy consumption. However, there exists a great challenge to achieve highly expanded microcellular polymer with satisfactory thermal insulation performance. Herein, polypropylene (PP) with carbon nanotubes (CNTs) was used to prepare multifunctional foams by using batch foaming process with carbon dioxide. This cost-efficient and facile process endowed PP/CNT composite a variety of unprecedented advantages, including over 50-fold expansion ratio, a rather low thermal conductivity of 28.69 mW/m·K, and remarkably improved compressive strength. Acting as both crystal and cell nucleating agents, CNTs contributed to the fabrication of such ultralight foams with refined cell structure, which led to significantly reduced solid thermal conduction and enhanced mechanical properties. Moreover, thanks to CNTs’ outstanding infrared radiation shielding capacity, the thermal radiation through the ultra-lightweight PP/CNT foam was significantly suppressed. Thus, ultra-lightweight, super thermal-insulation, and strong PP/CNT composite foams were achieved by using microcellular foaming technology, paving a way for designing and synthesizing multifunctional polymer-based composite foams for high-performance thermally insulating applications.

The Influence of Soft-Epitaxial Crystallization on Polyamide 66/Carbon Nanotubes Composite Injection Bar

The hydrogen–bonding-rich semi-crystalline polyamide 66 (PA66) was chosen to investigate the influence of soft-epitaxial effect on polymer/carbon nanotube (CNT) nanocomposite injection-molding bars, and the crystallization behavior was explored by differential scanning calorimeter (DSC), scanning electron microscope (SEM), two-dimensional wide angle X-ray diffraction (2D-WAXD) and two-dimensional small angle X-ray scattering (2D-SAXS). The results indicated that CNT is an effective nucleation agent for PA66 crystallization and the coupling of the flow and CNT can induce the soft-epitaxial crystallization of PA66 upon CNT surface, resulting in the coexistence of soft-epitaxial nanohybrid shish-kebab crystalline structure and conventional non-epitaxial crystals in PA66/CNT nanocomposites. Although the presence of CNT did not change the crystal structure of PA66, the generation and presence of soft-epitaxial crystals could feebly enhance the orientation degree of PA66 crystals and slightly improve the mechanical properties of PA66/CNT nanocomposites.

Low Li2O content study in Li2O-Al2O3-SiO2 glass-ceramics

The price of lithium-containing minerals and other chemical materials continues to increase, resulting in an increase in the production cost of Li2O-Al2O3-SiO2 (LAS) system glass-ceramics. In the LAS glass-ceramics component, the reduction in the amount of Li2O used can reduce the cost of the product. It is worthwhile to study whether it is possible to prepare glass-ceramics with low expansion properties under low Li2O content. The effect of Li2O content on the glass-ceramics of LAS system was studied. In this paper, spodumene was used as the main raw material, and TiO2 and ZrO2 were added as crystal nucleating agents to prepare transparent glass-ceramics with low expansion coefficient. The effects of the change of Li2O content on the crystal phase and microstructure of glass-ceramics were investigated by XRD, DSC, FTIR and SEM. The results show that the main crystalline phase of the low expansion transparent glass-ceramics is β-quartz solid solution. When Li2O content is in the range of 2.99 wt% to 4.13 wt%, low expansion glass ceramics can be prepared by an appropriate method. With the increase of Li2O content, the average coefficient of thermal expansion (CTE) in the temperature range of 30 °C–300 °C shows a decreasing trend. When Li2O content is in the range of 3.51 wt% to 4.13 wt%, the thermal expansion coefficient of the glass ceramics is extremely small, and even a negative expansion coefficient occurs.

Effect of chitosan incorporation on crystallinity, mechanical and rheological properties, and photodegradability of PE/TPS blends

Chitosan is a well-known biodegradable biopolymer, which possesses antimicrobial properties. In this study, the effect of chitosan incorporation on the morphology; thermal, mechanical, and rheological properties; and antibacterial and photodegradation behaviors of polyethylene (PE)/thermoplastic starch (TPS) blends were examined. PE/TPS blends were compatibilized with low-density PE-grafted maleic anhydride copolymer (PE- g-MA) compatibilizer. Scanning electron microscopy (SEM) and tensile test indicated that the addition of chitosan in powder form has a devastating effect on both mechanical and morphological properties of the blends. Therefore, chitosan was plasticized with acetic acid and glycerol (2 wt% chitosan dissolved in acetic acid/glycerol solution) prior to addition to the blends, which considerably improved the mechanical properties of the blends. Dynamic rheological experiments revealed a decrease in the complex viscosity of the blends with the addition of plasticized chitosan compared with unplasticized chitosan. SEM micrographs demonstrated more homogenous microstructure for the blends containing plasticized chitosan and PE- g-MA compatibilizer. Differential scanning calorimetry results indicated that unplasticized chitosan acts as a nucleation agent for PE crystallization. Antibacterial analysis indicated that the incorporation of chitosan had a significant effect on preventing from bacterial population growth. The major part of this article was to study the effect of ultraviolet (UV) exposure on the chemical structure and mechanical properties of the blends, using Fourier transform infrared spectroscopy and tensile properties examination. The results indicated that the slight amount of chitosan may significantly improve the photostability of PE/TPS blends against UV degradation. However, PE- g-MA compatibilizer dramatically decreased the UV resistance of the blends.

Fabrication of lightweight microcellular foams in injection-molded polypropylene using the synergy of long-chain branches and crystal nucleating agents

Herein, we have fabricated microcellular injection-molded foams by combining long-chain branched polypropylene (LCBPP) and 1,3:2,4 bis-O-(4-methylbenzylidene)-D-sorbitol gelling agent (MD) using a core-back foam injection molding (FIM) technique. Microcellular foams of LCBPP/MD blends having an average cell diameter of approximately 2.5 μm and a cell density on the order of 1010 cells/cm3 were achieved with a void fraction of 50%. Fast scanning chip calorimetry results revealed that the added MD acted as effective nucleating agents and promoted crystallization for the LCBPP. Interestingly, the development of microcellular foams led to notable advances in tensile toughness from 44.1 MJ/m3/(g·cm−3) and 111% of neat LCBPP foams to 172.1 MJ/m3/(g·cm−3) and 440% of LCBPP/MD blend foams in terms of specific breaking energy and elongation at break, respectively. These results revealed that the lightweight microcellular PP with improved toughness could be developed using FIM, which offers a viable approach to fabricate injection-molded products for large-scale applications.

Effect of Graphite Nanosheets on Properties of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

The influence of different contents, 0.25, 0.50, and 1.00 wt%, of graphite nanosheets (GNS) on the properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanocomposites obtained by solution casting method has been studied. GNS were prepared by three steps: intercalation (chemical exfoliation), expansion (thermal treatment), and the GNS obtainment (physical treatment by ultrasonic exfoliation). X-ray diffraction (XRD), Raman spectroscopy, and field emission gun-scanning electron microscopy (FE-SEM) showed that the physical, chemical, and thermal treatments preserved the graphite sheets structure. XRD and Raman results also showed that GNS were dispersed in the PHBV matrix. The degree of crystallinity (Xc) of the nanocomposites did not change when the graphite nanosheets were added. However, the GNS acted as nucleation agent for crystallization; that is, in the second heating the samples containing GNS showed two melting peaks. The addition the GNS did not change the thermal stability of the PHBV.

Development of PLA/cellulosic fiber composite foams using injection molding: Crystallization and foaming behaviors

Poly(lactic acid) (PLA) and northern bleached softwood kraft (NBSK) or black spruce medium density fiberboard (MDF) fibers were melt compounded using a co-rotating twin screw extruder and subsequently microcellular injection molded. Poly(ethlylene glycol) (PEG) was used as a lubricant. The microcellular structure, thermal properties, and crystallization behaviors were characterized using scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, and wide angle X-ray diffraction. Results show that cellulosic fibers, acting as crystal nucleating agents, increased the crystallization temperature and the crystallinity and decreased the crystallization half time. The dissolved N2, the shear stress, and biaxial stretching during foaming also enhanced the crystallinity of PLA. Compared to PLA/PEG, a finer and more uniform cell structure was achieved in the cellulosic fiber composite foams. The improved foam morphology was attributed to the cell nucleating effects of the fibers and the increased melt strength by the addition of cellulosic fibers and by the gas- and fiber- induced crystallization.

Preparation and foaming mechanism of foamable polypropylene based on self-assembled nanofibrils from sorbitol nucleating agents

A strategy to prepare foamable isotactic polypropylene (iPP) was proposed by introducing crystal nucleating agent, 1,3:2,4-bis(p-methylbenzylidene) sorbitol (S20), and the foaming mechanism was also investigated. When a proper concentration (above 0.3 wt%) of S20 was added, iPP/S20 exhibited excellent foaming performance, yielding uniform cells with well-defined structures and higher cell density than those of neat iPP. The results of rheological analysis and TEM confirmed the formation of S20 nanofibrils in iPP matrix. The existence of these nanofibrils increased the melt viscosity of iPP and enhanced the bubble nucleation in the foaming process, and thus should be responsible for the improved foaming ability of iPP. Moreover, iPP/S20 could be foamed in a remarkably wide temperature range from 143 to 163 °C. In comparison, another crystal nucleating agent, sodium 2,2′-methylene-bis-(4,6-di-tert-butylphenyl)-phosphate (NA40), contributed little to the foamability of iPP although it also induced the crystallization of iPP.

Non-isothermal crystallization behaviors of poly(lactic acid)/cellulose nanofiber composites in the presence of CO2

The effects of cellulose nanofiber (CNF) on the non-isothermal crystallization behaviors of poly(lactic acid) (PLA) at atmospheric pressure and at various CO2 pressures were investigated using a regular differential scanning calorimeter (DSC) and a high-pressure DSC at different cooling rates of 1, 2, 3, and 5°C/min. The POM images revealed that the CNFs acted as crystal nucleating agents, increasing the number of crystals and decreasing the crystal sizes. The non-isothermal crystallization showed that PLA’s crystallization rate increased with cooling rates and the incorporation of CNFs accelerated the overall crystallization kinetics by providing more nuclei, thereby decreasing the crystallization half-time. The degree of crystallinity was not proportional to the CO2 pressure. The highest crystallinity was obtained at a higher pressure with increased cooling rates. The activation energy analysis showed that the incorporation of CNFs restricted the movement of PLA molecular chains, thereby hindering crystallization. By comparing the Avrami analysis, Mo analysis, and activation energy results, it was speculated that heterogeneous crystal nucleation with the presence of CNFs might be the dominant factor in determining the overall non-isothermal crystallization rate of the PLA/CNF composites. Wide angle X-ray diffraction (WAXD) diffractograms showed that CNFs and CO2 pressure had no influence on the crystalline structure of PLA. The effects of CNF content, CO2 pressure, and cooling rate on Tc, Tm, and Tg were also investigated.