Virgin iPP Research Articles

(232) AGGRESSIVE REHABILITATION POST-IPP EXCHANGE: WE BLEW A GASKET

Abstract Introduction In our center, the majority of men undergoing virgin IPP are engaging in sexual activity from 14-21 days post-operatively. Our standard protocol in these patients is to leave cylinders completely deflated post-operatively without compressive dressing or foley catheter. A 10Fr Jackson Pratt closed suction drain is left for 48-72 hours. At 10-14 days patients are taught to cycle their device. In November 2023, we implemented an accelerated rehab to coitus algorithm for patients undergoing simple device exchanges as well. We interrogated the effect of this protocol change in IPP exchanges over a 6-month period. Objective To interrogate an accelerated post-IPP rehab protocol in simple exchange cases. Methods This is a retrospective review of virgin IPP insertions and exchange cases that occurred between November 2023 and May 2024. Inclusion criteria were uninfected revision cases for existing device malfunction for which all components were exchanged. In the month of November, post-op protocols were identical for virgin and exchange cases, except that two closed-suction drains were used in the latter. Data on post-operative course, complications and time to sexual activity were collected. Of note, post-exchange rehabilitation protocol was modified in December 2023. Following identification of 2 complications, all exchange cases were advised to leave device completely deflated for 6 weeks. Results In this 6-month period, there were 156 virgin IPP insertions. Of these men, 85% had engaged in sexual activity from 14-21 days post-operatively. All 156 remain without complication until the end of June 2024. There were 40 device exchanges in this period, all of which were successfully exchanged via infrapubic incision to Coloplast Titan IPP irrespective of the primary surgical approach or device. 6 exchanges occurred in November 2023 when the accelerated rehabilitation protocol was instituted. Of these 6 cases, 2 (33%) developed proximal cylinder herniation through the corporotomy site within 2 weeks of initiating sexual activity. This was the first exchange for both men. Neither patient, aged 58 and 70 years, have medical conditions that would impair normal healing. For the subsequent 34 exchanges, who did not activate their IPP for 6 weeks, there were no cylinder herniations. All 34 men were able to successfully cycle their device at 6 weeks without de-novo deformity. Conclusions While an accelerated rehabilitation protocol is safe for virgin cases, we observe that a longer duration of time is required for healing following non-virgin cases. Even in the absence of systemic factors or localised infection, the corporal tunica appears to behave differently following initial intervention and requires longer for corporal integrity to re-establish. Disclosure No.

(168) SPURIOUS SPOUT: ANTIMICROBIAL PRACTICES DURING IPP INSERTION – SINGLE CENTER EXPERIENCE

Abstract Introduction Penile prosthesis infection (PPI) remains a serious complication for men undergoing implant surgery with potentially devastating sequelae. Historically, PPI were noted to be predominantly gram-positive, such as coagulase-negative Staphylococcus species. More recently, top 3 PPI-isolated pathogens identified were Escherichia coli (18.3%), coagulase-negative Staphylococcus species (15%), and Candida (11.1%). Fear that inhibizone and liberal use of broad-spectrum antibiotics may be contributing to a new PPI organism profile and resistance patterns, antiseptic solutions have recently re-emerged. Irrisept is an FDA-approved off-the-shelf product, containing 0.05% chlorhexidine gluconate (CHG), has recently been heavily marketed. Promising in-vitro results have swayed some implanting surgeons to change their practice. Objective To detail our experience and results after completely switching to Irrisept during virgin IPP implantation. Methods This is a retrospective review of primary IPP cases that were performed by one surgeon in the same outpatient center. Between September and November 2023, Irrisept completely substituted the usual solution of Gentamicin, Vancomycin and Amphotericin B or Fluconazole for both device “dipping” and intraoperative irrigation. All other procedures, including pre-operative scrub and IV antibiotics on induction, remained unchanged. The outcomes of these patients were compared to those undergoing primary IPP in the preceding 9 months when the routine protocol was used (November 2022 – August 2023). Presented outcomes represent follow-up from date of primary implant to 31st May 2024. Results In the 3 months that Irrisept was used, 60 primary implants were performed and two became infected (3.3%). Both manifested with pain and purulent exudate egress from their infrapubic wounds. Both underwent successful salvage to malleable prosthesis. Only one case yielded a positive wound culture, growing Klebsiella pneumoniae (pan-sensitive, except to Ampicillin). In contrast, 243 primary implants were performed in the 9 months prior without any infection (0%). Conclusions The in-vitro claims of Irrisept, with respect to Kinetic-Kill Time and logarithmic reduction in bacterial/fungal colony counts, did not translate to our in-vivo experience. Further multicenter studies are necessary to interrogate the use of this product in prosthetic urology. Disclosure No.

PD42-01 DRAINED VERSUS NON-DRAINED INFLATABLE PENILE PROSTHESIS IMPLANTATION: A MULTICENTER PROSPECTIVE PILOT STUDY ON A LARGE COHORT

You have accessJournal of UrologyCME1 Apr 2023PD42-01 DRAINED VERSUS NON-DRAINED INFLATABLE PENILE PROSTHESIS IMPLANTATION: A MULTICENTER PROSPECTIVE PILOT STUDY ON A LARGE COHORT Daniar Osmonov, Ahmed Ragheb, Petry Tim, Ahmed Eraky, Carlo Bettocchi, Glenn Lamers, Koenraad Van Renterghem, Marina Tropmann-Frick, Klaus-Peter Jünemann, Giulio Garaffa, Hartmut Porst, Ahmed Mohamed, and Steven Wilson Daniar OsmonovDaniar Osmonov More articles by this author , Ahmed RaghebAhmed Ragheb More articles by this author , Petry TimPetry Tim More articles by this author , Ahmed ErakyAhmed Eraky More articles by this author , Carlo BettocchiCarlo Bettocchi More articles by this author , Glenn LamersGlenn Lamers More articles by this author , Koenraad Van RenterghemKoenraad Van Renterghem More articles by this author , Marina Tropmann-FrickMarina Tropmann-Frick More articles by this author , Klaus-Peter JünemannKlaus-Peter Jünemann More articles by this author , Giulio GaraffaGiulio Garaffa More articles by this author , Hartmut PorstHartmut Porst More articles by this author , Ahmed MohamedAhmed Mohamed More articles by this author , and Steven WilsonSteven Wilson More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003352.01AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Despite the wide utilization of post-inflatable penile prosthesis (IPP) implantation drainage, many surgeons still regard it as a potential source of infection. Our aim was to understand the risks and benefits of post-IPP drainage and optimal duration. METHODS: Patients underwent IPP implantation for the first time by four European high volume surgeons through penoscrotal access receiving similar perioperative antibiotics. They were divided into 3 groups based on the presence and duration of drainage. Group 1 (n=114) had no drain placed, Group 2 had a drain placed for 24 hours (n=114) and Group 3 had a drain placed for 72 hours (n=117). The presence or absence of postoperative (PO) scrotal hematoma and prosthesis infection were evaluated and compared between the groups via scrotal ultrasound (US) examination carried out 24 hours then 3 and 10 days PO. All patients were followed up postoperatively for a minimum of 80 days. RESULTS: The patients from Group 3 demonstrated a statistically significant lower incidence of hematoma on the 10th PO day: (n=1, 0.9%) compared to Group 2: (n=11, 9.6%) and Group 1: (n=8, 7%, p=0.013). However, on the 3rd PO day, which showed the highest hematoma prevalence, there was a statistically significant lower incidence of hematoma in Groups 3 and 2: (0.9% and 7%, respectively) versus Group 1: (11.4%, p=0.004). Hematoma rates followed the same order after the first day of surgery for Groups 1-3: 8.8% (n=10), 5.3% (n=6), and 1.7% (n=2), respectively. (p=0.054). Five patients (4.4%) in Group 1 and four patients (3.5%) in Group 2 developed an IPP associated infection, opposed to only a single patient (0.85%) in Group 3. CONCLUSIONS: Prolonged scrotal drainage for 72 hours after virgin IPP implantation significantly reduces hematoma and infection rates. It is likely that hematoma formation per se, is a predisposing factor for IPP infection. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e1111 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Daniar Osmonov More articles by this author Ahmed Ragheb More articles by this author Petry Tim More articles by this author Ahmed Eraky More articles by this author Carlo Bettocchi More articles by this author Glenn Lamers More articles by this author Koenraad Van Renterghem More articles by this author Marina Tropmann-Frick More articles by this author Klaus-Peter Jünemann More articles by this author Giulio Garaffa More articles by this author Hartmut Porst More articles by this author Ahmed Mohamed More articles by this author Steven Wilson More articles by this author Expand All Advertisement PDF downloadLoading ...

Increasing role of counterincision for high submuscular penile prosthesis reservoir placement

AbstractBackgroundInflatable penile prosthesis (IPP) reservoir placement into the high submuscular (HSM) space is safe and well tolerated. Recent studies have proposed that reservoirs placed via an abdominal counterincision (CI) may offer more precise and durable positioning as compared with a transinguinal (TI) approach.AimHerein we compare the CI-HSM and TI-HSM techniques with respect to operative time, pain control, and postoperative complications.MethodsWe reviewed our penile prosthesis database at a large single-surgeon tertiary referral center from 2014 to 2021 to compare those who underwent virgin reservoir placement via the CI-HSM technique vs the TI-HSM technique. Statistical analysis was performed with the Mann-Whitney U test for continuous variables and the chi-square test and Fisher exact test for discrete variables.OutcomesOperative time, postoperative complications, morphine milligram equivalents prescribed, and postoperative correspondence were compared between patients undergoing the CI-HSM and TI-HSM techniques.ResultsAmong 456 virgin IPP implants, the CI-HSM technique was used in 34 cases (7.5%) and the TI-HSM technique in 422 cases (92.5%). Of these 456 cases, 92 (20.2%) were combined with ancillary procedures such as artificial urinary sphincter, urethral sling, or penile plication (6/34, CI; 86/422, TI). Cases employing the CI-HSM technique had a 19.9% greater median operative time: 81.5 minutes (IQR, 69.3-106.5) vs 68 minutes (IQR, 57.8-80.3; P < .01). A similar proportion of patients in the CI-HSM group (2/34, 5.9%) were treated for infection as in the TI-HSM group (17/422, 4.0%; P = .64). Reservoir herniation was seen in 12 patients in the TI-HSM group (2.8%) and in none of the CI-HSM group, but this did not reach significance (P > .99). No differences were identified between patients in the TI-HSM and CI-HSM groups with regard to postoperative morphine milligram equivalents prescribed, narcotic medication refills, or postoperative correspondence.Clinical ImplicationsCI-HSM reservoir placement was associated with similar surgical outcomes to TI-HSM without increased infection risk or need for narcotic pain management.Strengths and LimitationsAlthough this study is a large contemporary series addressing a clinically important subject, it is limited by its retrospective preliminary nature and nonrandomized unmatched design. Patient pain regimens were assessed via discharge prescriptions, although data regarding narcotic consumption were not available in the medical record.ConclusionsIPP reservoir placement via the CI-HSM technique is safe and well tolerated. Increased operative time of the CI-HSM technique as compared with the TI-HSM technique is clinically negligible given its potential safety benefits of direct visualization of reservoir placement.

Recycling of metallocene isotactic polypropylene: importance of antioxidants

Recycling of plastics is absolutely essential in a circular economy, especially in the case of commodity polymers from fossil resources, like isotactic polypropylene (iPP). Therefore, evaluation of the factors that are decisive for an optimum performance of the recycled based materials becomes mandatory for the obtainment of new products with optimal properties. One of the most important aspects is the protection of the plastics materials not only against the external degradation agents, but also from the radicals generated during their previous service life. Accordingly, several materials have been prepared by extrusion based on virgin iPP with different amounts of the same polypropylene severely degraded, which has been used as model component to be recycled. Previous to the extrusion, a mixture of antioxidants was added to all the samples, and special attention has been paid to consumption of those additives during the extrusion. The results show an increasing reduction of antioxidants with rising content of the degraded material. But, importantly, a rather analogous mechanical response has been found for all the recycled materials in relation to the virgin iPP, pointing out a satisfactory dilution effect of the existing degradation points within the virgin polymeric chains, and indicating the very relevant action of the antioxidants used.

Radiographic Assessment of Inflatable Penile Prosthesis Reservoir Location Variability in Contemporary Practice

ABSTRACT Introduction Inflatable penile prosthesis (IPP) reservoirs are typically placed into the Space of Retzius (SOR), High Submuscular Space (HSM), or alternative locations via a transinguinal (TI) approach or a lower abdominal counter incision (CI). A cadaver study showed variability in reservoir location after TI-HSM placement (JSM: 2016 Sep;13(9):1425-1431). Objective We sought to evaluate reservoir location using cross-sectional imaging following contemporary IPP insertion. Methods We retrospectively reviewed our institutional database and identified men who underwent virgin penoscrotal IPP insertion from 2007 to 2019. We then identified those men who subsequently underwent cross-sectional imaging prior to October 2019. Radiologists blinded to reservoir placement technique evaluated cross-sectional imaging and categorized each reservoir location in relation to the abdominal wall musculature, transversalis fascia, and peritoneum. Statistical analysis was performed using Chi-squared and Fisher's exact tests. Results Among 561 men who underwent virgin IPP insertion during the 12 year study period, 114 had cross-sectional imaging subsequently obtained: 29 TI-SOR, 80 TI-HSM, and 5 CI-HSM (Table). TI-HSM reservoirs were more likely than TI-SOR to be located anterior to the transversalis fascia (14 vs. 48%, p=0.001). TI-HSM reservoirs were less likely than TI-SOR to be located in the preperitoneal space (62 vs. 18%, p<0.001). Rates of retroperitoneal reservoir location were similar between the TI-HSM and TI-SOR groups. Among all 561 patients (131 TI-SOR, 405 TI-HSM, and 25 CI-HSM), rates of reservoir-related complications requiring operative intervention were similar between groups (5 vs. 2 vs. 0%, p = 0.24). Conclusions Roughly half of the TI-HSM reservoirs in this series appeared to be located posterior to the transversalis fascia on cross-sectional imaging. Although preperitoneal and retroperitoneal locations were common in both groups, reservoir related complications were rare. Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: Boston Scientific and Coloplast

Influence of isotactic polypropylene grafted with styryl-group on the polymer crystallization behavior

4-Furfuryloxymethylstyrene (Sf) grafted isotactic polypropylene (iPP-g-Sf) was prepared by melt grafting reaction. The crystallization temperature of iPP after grafting increased to ∼130 °C. The isothermal and non-isothermal crystallization kinetics of iPP-g-Sf containing up to 1.50 mol% grafted Sf groups were compared with that of virgin iPP, and the isothermal and non-isothermal crystallization kinetics parameters of the polymers, including the fold surface free energy σe, the chain folding work q, and the crystallization activation energy ΔE, were calculated by Lauritzen-Hoffman theory and Kissinger method respectively. The results showed that iPP-g-Sf exhibited a unique self-nucleation phenomenon, which accelerating the crystallization rate of iPP and produced tiny crystal morphology than that for iPP. The introduction of only 0.23–1.50 mol% grafted Sf groups reduced the σe of the crystals by 44–57%. This might provide guidance for the design of polymer crystallization rate by controlling the molecular structures.

Isothermal Crystallization of iPP in Environment-friendly Diluents: Effect of Binary Diluents and Crystallization Temperature on Crystallization Kinetics

The growing demand for non-toxic solvents for membrane preparation has motivated the studies for green and sustainable alternatives of solvents. The effect of droplet isothermal growth within the liquid-liquid phase separation region on isothermal spherulitic growth rate of isotactic polypropylene (iPP) was investigated. The results showed that the droplets grew up at a rate of 0.0172 μm·s−1. The larger droplets slowed down the isothermal spherulitic growth rate of iPP. Higher mass ratio of carnauba wax (Cwax)/soybean oil (SO) resulted in faster droplet growth due to weak interaction with polymers. The isothermal crystallization behaviors of iPP in environment-friendly binary diluents consisting of Cwax and SO mixture were further investigated experimentally using polarized optical microscopy. It was demonstrated that the isothermal spherulitic growth rate of iPP in diluents decreased nonlinearly with the increasing crystallization temperature. Compared with virgin iPP, isothermal spherulitic growth rate of iPP in SO diluent was significantly slowed down. The spherulitic growth was further retarded after the addition of Cwax in mixed diluents, resulting in a lower crystallization rate than that in SO. Moreover, the crystal form of iPP membranes was found to be α type through the characterization of small angle X-ray scattering and wide angle X-ray diffraction.

Crystallization kinetics of isotactic polypropylene nucleated with octamethylenedicarboxylic dibenzoylhydrazide under isothermal and non-isothermal conditions

Octamethylenedicarboxylic dibenzoylhydrazide (TMC-300) was used as a nucleating agent for isotactic polypropylene (iPP) for the first time. The Avrami method and the Caze method were used to analyze the isothermal and non-isothermal crystallization kinetics of iPP incorporated with TMC-300, respectively. During isothermal crystallization, the half crystallization time at 130 °C reduces from 130 s of virgin iPP to 44 s after addition of TMC-300, which reflects that TMC-300 increased the crystallization rate of iPP obviously. The crystallization activation energy decreases from 382.5 kJ mol−1 of virgin iPP to 275.3 kJ mol−1 of iPP/TMC-300. During non-isothermal crystallization, the crystallization peak temperature of iPP nucleated with TMC-300 was increased by 5.1 °C when compared to that of virgin iPP at the cooling rate of 20 °C min−1, and both the reduction of half crystallization time and the increase in peak crystallization temperature also justified that the addition of TMC-300 accelerated the crystallization of iPP.

Nucleus density dependency of crystallization of isotactic polypropylene nucleated with nucleating agent sodium bicyclic[2,2,1]heptane dicarboxylate

Sodium bicyclic[2,2,1]heptane dicarboxylate (HPN-68) is a highly effective commercial isotactic polypropylene (iPP) nucleating agent. In this paper, isothermal crystallization behaviors of iPP nucleated with HPN-68 were investigated using differential scanning calorimetry (DSC). The calculation model of Lamberti based on the Avrami method was used for obtaining nucleus density from calorimetric crystallization curves recorded under isothermal conditions. A number of growth rate data have been obtained with the Lauritzen and Hoffman equation. General procedures to predict nucleus density by simple DSC measurements were described and applied successfully to iPP. Addition of HPN-68 shortened crystallization half-time (t 1/2) and increased the crystallization rate of iPP, eventually the nucleus density of iPP nucleated with HPN-68 for finishing crystallization under higher crystallization temperature was larger than that of virgin iPP, leading to larger crystallization rate and shorter cycle time.

Isothermal Crystallization of Isotactic Polypropylene Nucleated with a Novel Aromatic Heterocyclic Phosphate Nucleating Agent

ABSTRACTThe incorporation of a nucleating agent into isotactic polypropylene (iPP) is one of the most important and widely used methods to improve performance in the polypropylene industry. Aromatic heterocyclic phosphate salt is a kind of highly effective nucleating agent for iPP and one of the typical products is a compound nucleating agent based on 2, 2-methylene-bis (4, 6-di-tert-butylphenyl) phosphate hydroxyl aluminum (commercial product name: ADK NA-21). In this paper the isothermal crystallization kinetics of iPP nucleated with the α-nucleating agent NA-21, investigated using differential scanning calorimetry (DSC), is described with the crystallization data being analyzed by using the classic Avrami method. During isothermal crystallization the addition of nucleating agent NA-21 dramatically shortened the crystallization half time (t1/2) of iPP under the same conditions and the crystallization activation energy, ΔE, decreased from 422 kJ/mol for virgin iPP to 369 kJ/mol with the addition of NA-21. Thus, the addition of NA-21 significantly increased the crystallization rate of iPP.

Effects of cyclic carboxylate nucleating agents on nucleus density and crystallization behavior of isotactic polypropylene

Isothermal crystallization behavior of isotactic polypropylene (iPP) nucleated with three cyclic carboxylate nucleating agents, namely, sodium bicyclic[2,2,1] heptane dicarboxylate (HPN-68), sodium benzoate (Be-Na), and sodium salt of hexahydrophthalic acid (HHPA-Na), was investigated by using differential scanning calorimetry. The classical Avarmi method was used to evaluate the isothermal crystallization behavior of iPP. The nucleus density was obtained by the calculation model of Lamberti based on the Avrami method of crystallization kinetics from calorimetric crystallization curves recorded under isothermal conditions. This method was able to measure nucleus density and growth rate of nucleated iPP, for which the nucleation phenomenon was substantially heterogeneous. The addition of nucleating agents shortened the crystallization halftime (t 1/2) and increased the crystallization rate of iPP under isothermal crystallization, eventually increasing the nucleus density of iPP nucleated with nucleating agents for finishing crystallization under higher crystallization temperature, which was larger than that of virgin iPP. The results of polarized optical microscopy also showed that the nucleus density and crystallization rate were greatly increased with addition of nucleating agents. In these three nucleating agents, HPN-68 had the best nucleation effect, and iPP nucleated with HPN-68 had shorter crystallization halftime and higher nucleus density than iPP nucleated with Be-Na and HHPA-Na.

Joint effects of molecular structure and crystal morphology of organophosphate monovalent salts on nucleated isotactic poly(propylene)

The nucleation ability of organophosphate monovalent salts in isotactic poly(propylene) (iPP) was elucidated from the crystalline morphology and molecular structure with different size of cationic radius (r) of substitute parts. Differential scanning calorimetry result showed that the degree of crystallinity of nucleated iPP increased linearly with the increasing of r following the order of lithium (NA-10), sodium (NA-11), potassium (NA-12), ammonium (NA-13) salts of 2,2′-methylene- bis-(4,6-di-t-butylphenylene) phosphate. Moreover, small-angle X-ray scattering result displayed a large increase in the periodical length of nucleated iPP, which arises from an increment of both lamella thickness and amorphous thickness. Further, at 0.15 wt% concentration, the haze values of nucleated iPP presented a decrease tendency in the order of iPP/NA-10 (16.7 %), iPP/NA-11 (15.1 %), iPP/NA-12 (14.6 %), iPP/NA-13 (14.8 %), and their flexural strength was increased by 26.2 %, 30.8 %, 31.4 % and 31.7 %, respectively, as comparison to virgin iPP. These results demonstrated that the nucleating ability of these nucleating agents increased with the increase of r of substitute parts.

A Novel Strategy for Achieving High Melt Strength Polypropylene and an Investigation of Its Foamability

A novel and feasible strategy for preparing high melt strength polypropylene (HMSPP) was developed by a melt grafting reaction in the presence of macro-monomer vinyl polydimethylsiloxane (VS), co-monomer styrene (St), and initiator benzoyl peroxide through a one-step reactive extrusion. The rheological behaviors, melt strength, and foaming ability of HMSPP were studied. The results showed that VS and St were successfully grafted onto polypropylene (PP), and the weight average molecular weight, molecular weight distribution, and melt strength of HMSPP were dramatically increased compared with those of the virgin isotactic polypropylene (iPP). Especially, the melt strength of HMSPP increased from 0.022 N for the virgin iPP to 0.29 N, which made the foamability of HMSPP significantly improved when supercritical carbon dioxide was used as the blowing agent. The foaming condition was optimized to 160°C and 14 MPa, for which HMSPP foams with a high expansion ratio of 66 times and a high cell density of about 5.8×107 cell/cm3 were obtained, while the virgin iPP did not yield foams with good cell structure. Moreover, the resultant HMSPP could be foamed in a remarkably wide temperature range from 145°C to 165°C, which would be of great significance for industrial application.

Isothermal and non-isothermal crystallization of isotactic polypropylene nucleated with 1,3,5-benzenetricarboxylic acid tris(cyclohexylamide)

Abstract Isothermal and non-isothermal crystallization kinetics of isotactic polypropylene (iPP) nucleated with 1,3,5-benzenetricarboxylic acid tris(cyclohexylamide) (BTCA-TCHA) were investigated by differential scanning calorimetry (DSC). The classical Avarmi equation and the Mo method were used to analyze the experimental data. The results showed the Avrami equation and the Mo method described the isothermal and non-isothermal crystallization processes of iPP accurately, respectively. During isothermal crystallization, addition of BTCA-TCHA shortened half crystallization time (t1/2) and increased crystallization rate of iPP greatly. In addition, addition of BTCA-TCHA decreased the crystallization activation energy ΔE from 370 kJ/mol of virgin iPP to 312 kJ/mol. During non-isothermal crystallization, half time of the crystallization (t1/2) of virgin iPP was larger than that of nucleated iPP under the same cooling rate and the required cooling rate of virgin iPP to reach the same relative crystallinity was higher than that of nucleated iPP, indicating that addition of BTCA-TCHA increased the crystallization rate obviously.

Thermal Stability and Kinetic Study of Isotactic Polypropylene/Algerian Bentonite Nanocomposites Prepared via Melt Blending

Isotactic polypropylene (iPP)/bentonite nanocomposites were prepared via melt blending using bentonite clay originated from Maghnia (Algeria). This clay was, at a first stage, used in its pure form (PBT) and then organically modified by Hexadecyl ammonium chloride (OBT). The effect of Maghnia bentonite dispersion on the iPP matrix was investigated by X-ray diffraction (XRD) and transmission electronic microscopy (TEM). DSC results evidenced that unmodified or organomodified bentonite can act as a nucleating agent increasing the rate of crystallites formation. Moreover, a thermogravimetry analysis confirmed a significant enhanced thermal stability of IPP/clay nanocomposites compared to pure IPP. The Flynn-Wall-Ozawa and Tang methods were applied to determine the activation energy Ea of the degradation process. The apparent activation energy Eα of thermal degradation for IPP/clay nanocomposites was much higher than that of virgin iPP. Comparatively to PBT, results indicate that OBT has an important effect on pure iPP thermal stability. Tensile modulus, tensile strength, and elongation at break were also measured and compared with those of pure iPP.

Preparation and foamability of high melt strength polypropylene based on grafting vinyl polydimethylsiloxane and styrene

A novel strategy was developed by melt grafting reaction in the presence of macromonomer vinyl polydimethylsiloxane (VS) and comonomer styrene (St) for preparing high melt strength polypropylene (HMSPP), and the rheological behavior, melt strength, and foaming ability of HMSPP were investigated. The results showed that VS and St were successfully grafted onto isotactic polypropylene (iPP), and the melt strength of HMSPP increased by more than 12 times compared to that of the virgin iPP. Moreover, HMSPP exhibited excellent foaming ability with smaller cell size, higher cell density, and higher expansion ratio compared to the virgin iPP when supercritical carbon dioxide was used as the blowing agent. POLYM. ENG. SCI., 55:251–259, 2015. © 2014 Society of Plastics Engineers

Effects of nucleating agent 1,3,5-benzenetricarboxylic acid tris(cyclohexylamide) on properties and crystallization behaviors of isotactic polypropylene

Amide derivatives of 1,3,5-benzenetricarboxylic acid are a type of novel nucleating agents for isotactic polypropylene (iPP). Effects of nucleating agent 1,3,5-benzenetricarboxylic acid tris(cyclohexylamide) (BTCA-TCHA) on properties and crystallization behaviors of iPP were investigated and the results were compared with those of iPP nucleated with a highly effective commercial nucleating agent Millad 3988. The results showed that BTCA-TCHA was highly effective and it improved greatly the mechanical and optical properties of iPP and increased crystallization peak temperature of iPP obviously. When the addition concentration of BTCA-TCHA was 0.2 wt.%, tensile strength and flexural modulus of iPP were increased by 9.7 and 12.4 %, respectively, and the haze value of iPP was decreased by 53.5 %. When the cooling rate was 20 °C/min, the crystallization peak temperature of iPP was increased from 114.6 °C of virgin iPP to 126.8 °C. In addition, it was found that the nucleation efficiency of BTCA-TCHA was comparable for that of Millad 3988.

Effects of α/β Compound Nucleating Agents on Mechanical Properties and Crystallization Behaviors of Isotactic Polypropylene

Sodium 2,2’-methylene-bis (4,6-di-tert-butylphenyl) phosphate (commercial name: Irgastab NA-11) and N,N’-dicyclohexylnaphthalene-2,6-dicarboxamide (commercial name: NU-100) are highly effective nucleating agents for α-isotactic polypropylene (iPP) and β-isotactic polypropylene (iPP) respectively. Effects of a total concentration of 0.2 wt% NA-11/NU-100 compound nucleating agents with different ratios of NU-100 on mechanical properties and crystallization behaviors of iPP were studied in this paper. The results showed that good balance between decreased stiffness and increased toughness of iPP was realized when the ratio of NU-100 was 50 wt%. Compared with those of virgin iPP, tensile strength, tensile modulus, flexural strength, and flexural modulus of iPP nucleated by the compound nucleating agent with 50 wt% NU-100 decreased by only 2.9%, 4.8%, 3.8% and 6.1% respectively, while the notched Izod impact strength of the nucleated iPP was increased by 212.8%. In addition, differential scanning calorimetry analysis results showed that addition of the NA-11/NU-100 compound nucleating agent increased the peak crystallization temperature of iPP significantly, but the crystallization rate of the nucleated iPP decreased with increasing ratio of NU-100 in compound nucleating agents.

Morphology, mechanical, and crystallization behaviors of micro- and nano-ZnO filled polypropylene composites

The aim of this study was to study the effect of ZnO concentration on the morphology, mechanical, and crystallization behaviors of iPP. Three compositions of iPP/mZnO and iPP/nZnO composites were prepared in a co-rotational twin-screw extruder machine with ZnO content of 2 wt%, 5 wt%, and 8 wt%. Tensile tests showed that the tensile strength at yield and tensile modulus of the composites tended to increase with increasing contents of mZnO/nZnO particles. This improvement in the tensile properties was attributed to good interfacial adhesion between the fillers and the matrix, as evidenced by TEM examination. The tensile strength at yield and tensile modulus values of iPP/nZnO composite with the addition of 2–8 wt% nZnO are higher than those of virgin iPP, and even higher than those of iPP/mZnO composite with the addition of 2–8 wt% mZnO. The non-isothermal crystallization behavior of iPP/mZnO and iPP/nZnO composites was investigated using DSC. The results indicated that the interfacial interaction between iPP and mZnO/nZnO increased the crystallization temperature when the content of ZnO is 5 wt%.