{"title":"Rheological analysis of network structure of raw natural rubber prepared by different processing techniques","authors":"","doi":"10.1016/j.polymertesting.2024.108608","DOIUrl":null,"url":null,"abstract":"<div><div>The performance of raw natural rubber (NR) is dominated by its network structure, particular the levels of long chain branching (LCB) and entanglement. Here, three type of raw rubbers were prepared using different processing methods for commercial grade NRs. Linear and nonlinear viscoelastic behaviors, as well as stress relaxation, were analyzed to access their network structures. The third relative harmonic, phase angle, and first to second quarter-period integral ratio of stress curve were utilized as indicators for the nonlinearity of samples. By combining these values with flow activation energy and characteristic times, it can be confirmed that naturally coagulated NR showed higher elasticity than acid-coagulated NR due to high levels of LCB and entanglement, and hot air drying could lead to chain degradation. These findings correlated with molecular weight parameters, gel content and Mooney viscosity results. This research establishes a method for monitoring raw NR quality and predicting its properties.</div></div>","PeriodicalId":20628,"journal":{"name":"Polymer Testing","volume":null,"pages":null},"PeriodicalIF":5.0000,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Polymer Testing","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S014294182400285X","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATERIALS SCIENCE, CHARACTERIZATION & TESTING","Score":null,"Total":0}
引用次数: 0
Abstract
The performance of raw natural rubber (NR) is dominated by its network structure, particular the levels of long chain branching (LCB) and entanglement. Here, three type of raw rubbers were prepared using different processing methods for commercial grade NRs. Linear and nonlinear viscoelastic behaviors, as well as stress relaxation, were analyzed to access their network structures. The third relative harmonic, phase angle, and first to second quarter-period integral ratio of stress curve were utilized as indicators for the nonlinearity of samples. By combining these values with flow activation energy and characteristic times, it can be confirmed that naturally coagulated NR showed higher elasticity than acid-coagulated NR due to high levels of LCB and entanglement, and hot air drying could lead to chain degradation. These findings correlated with molecular weight parameters, gel content and Mooney viscosity results. This research establishes a method for monitoring raw NR quality and predicting its properties.
天然橡胶(NR)生胶的性能主要取决于其网络结构,尤其是长链分支(LCB)和缠结程度。本文采用不同的加工方法制备了三种商用级天然橡胶生胶。分析了它们的线性和非线性粘弹行为以及应力松弛,以了解它们的网络结构。应力曲线的三次相对谐波、相位角和第一至第二四分之一周期积分比被用作样品非线性的指标。通过将这些值与流动活化能和特征时间相结合,可以确认自然凝固的 NR 由于高水平的 LCB 和缠结而比酸凝固的 NR 表现出更高的弹性,而热空气干燥可能会导致链降解。这些发现与分子量参数、凝胶含量和门尼粘度结果相关。这项研究建立了一种监测未加工 NR 质量和预测其特性的方法。
期刊介绍:
Polymer Testing focuses on the testing, analysis and characterization of polymer materials, including both synthetic and natural or biobased polymers. Novel testing methods and the testing of novel polymeric materials in bulk, solution and dispersion is covered. In addition, we welcome the submission of the testing of polymeric materials for a wide range of applications and industrial products as well as nanoscale characterization.
The scope includes but is not limited to the following main topics:
Novel testing methods and Chemical analysis
• mechanical, thermal, electrical, chemical, imaging, spectroscopy, scattering and rheology
Physical properties and behaviour of novel polymer systems
• nanoscale properties, morphology, transport properties
Degradation and recycling of polymeric materials when combined with novel testing or characterization methods
• degradation, biodegradation, ageing and fire retardancy
Modelling and Simulation work will be only considered when it is linked to new or previously published experimental results.